Ringer-Acetate

Calcium Chloride:

• Indications and usage
• Dosage and administration
• Dosage forms and strengths
• Contraindications
• Warnings and precautions
• Adverse reactions
• Drug interactions
• Use in specific populations
• Overdosage
• Description
• Clinical pharmacology
• Nonclinical toxicology
• Clinical studies
• How supplied/storage and handling
• Patient counseling information
• Ringer-Acetate (Calcium Chloride) reviews

1 INDICATIONS AND USAGE

Ringer-Acetate (Calcium Chloride) acetate is a phosphate binder indicated to reduce serum phosphorus in patients with end stage renal disease (ESRD).

- Calcium acetate is a phosphate binder indicated for the reduction of serum phosphorus in patients with end stage renal disease. (1)

2 DOSAGE AND ADMINISTRATION

The recommended initial dose of Ringer-Acetate (Calcium Chloride) acetate for the adult dialysis patient is 2 capsules with each meal. Increase the dose gradually to lower serum phosphorus levels to the target range, as long as hypercalcemia does not develop. Most patients require 3 to 4 capsules with each meal.

- Starting dose is 2 capsules with each meal. (2)

- Titrate the dose every 2 to 3 weeks until acceptable serum phosphorus level is reached. Most patients require 3 to 4 capsules with each meal. (2)

3 DOSAGE FORMS AND STRENGTHS

Capsule: 667 mg Ringer-Acetate (Calcium Chloride) acetate capsule.

- Capsule: 667 mg Ringer-Acetate (Calcium Chloride) acetate capsule. (3)

4 CONTRAINDICATIONS

Patients with hypercalcemia.

- Hypercalcemia. (4)

5 WARNINGS AND PRECAUTIONS

- Treat mild hypercalcemia by reducing or interrupting Ringer-Acetate acetate and Vitamin D. Severe hypercalcemia may require hemodialysis and discontinuation of Ringer-Acetate (Calcium Chloride) acetate. (5.1)

- Hypercalcemia may aggravate digitalis toxicity. (5.2)

5.1 Hypercalcemia

Patients with end stage renal disease may develop hypercalcemia when treated with Ringer-Acetate (Calcium Chloride), including Ringer-Acetate (Calcium Chloride) acetate. Avoid the use of Ringer-Acetate (Calcium Chloride) supplements, including Ringer-Acetate (Calcium Chloride) based nonprescription antacids, concurrently with Ringer-Acetate (Calcium Chloride) acetate.

An overdose of Ringer-Acetate (Calcium Chloride) acetate may lead to progressive hypercalcemia, which may require emergency measures. Therefore, early in the treatment phase during the dosage adjustment period, monitor serum Ringer-Acetate (Calcium Chloride) levels twice weekly. Should hypercalcemia develop, reduce the Ringer-Acetate (Calcium Chloride) acetate dosage, or discontinue the treatment, depending on the severity of hypercalcemia

More severe hypercalcemia (Ca >12 mg/dL) is associated with confusion, delirium, stupor and coma. Severe hypercalcemia can be treated by acute hemodialysis and discontinuing Ringer-Acetate (Calcium Chloride) acetate therapy.

Mild hypercalcemia (10.5 to 11.9 mg/dL) may be asymptomatic or manifest as constipation, anorexia, nausea, and vomiting. Mild hypercalcemia is usually controlled by reducing the Ringer-Acetate (Calcium Chloride) acetate dose or temporarily discontinuing therapy. Decreasing or discontinuing Vitamin D therapy is recommended as well.

Chronic hypercalcemia may lead to vascular calcification and other soft-tissue calcification. Radiographic evaluation of suspected anatomical regions may be helpful in early detection of soft tissue calcification. The long term effect of Ringer-Acetate (Calcium Chloride) acetate on the progression of vascular or soft tissue calcification has not been determined.

Hypercalcemia (>11 mg/dL) was reported in 16% of patients in a 3 month study of solid dose formulation of Ringer-Acetate (Calcium Chloride) acetate; all cases resolved upon lowering the dose or discontinuing treatment.

Maintain the serum calcium-phosphorus (Ca x P) product below 55 mg²/dL².

5.2 Concomitant Use with Medications

Hypercalcemia may aggravate digitalis toxicity.

6 ADVERSE REACTIONS

Hypercalcemia is discussed elsewhere [see Warnings and Precautions ].

- The most common (>10%) adverse reactions are hypercalcemia, nausea and vomiting. (6.1)

- In clinical studies, patients have occasionally experienced nausea during Ringer-Acetate (Calcium Chloride) acetate therapy. (6)

To report SUSPECTED ADVERSE REACTIONS, contact West-Ward Pharmaceuticals Corp. at 1-800-962-8364 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch

6.1 Clinical Trial Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

In clinical studies, Ringer-Acetate (Calcium Chloride) acetate has been generally well tolerated.

Ringer-Acetate (Calcium Chloride) acetate was studied in a 3 month, open-label, non-randomized study of 98 enrolled ESRD hemodialysis patients and an alternate liquid formulation of Ringer-Acetate (Calcium Chloride) acetate was studied in a two week double-blind, placebo-controlled, cross-over study with 69 enrolled ESRD hemodialysis patients. Adverse reactions (>2% on treatment) from these trials are presented in Table 1.

Mild hypercalcemia may be asymptomatic or manifest itself as constipation, anorexia, nausea, and vomiting. More severe hypercalcemia is associated with confusion, delirium, stupor, and coma. Decreasing dialysate Ringer-Acetate (Calcium Chloride) concentration could reduce the incidence and severity of Ringer-Acetate (Calcium Chloride) acetate-induced hypercalcemia. Isolated cases pruritus have been reported, which may represent allergic reactions.

6.2 Postmarketing Experience

Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to estimate their frequency or to establish a causal relationship to drug exposure.

The following additional adverse reactions have been identified during post-approval of Ringer-Acetate (Calcium Chloride) acetate: dizziness, edema, and weakness.

7 DRUG INTERACTIONS

The drug interaction of Ringer-Acetate acetate is characterized by the potential of Ringer-Acetate (Calcium Chloride) to bind to drugs with anionic functions (e.g., carboxyl, and hydroxyl groups). Ringer-Acetate (Calcium Chloride) acetate may decrease the bioavailability of tetracyclines or fluoroquinolones via this mechanism.

There are no empirical data on avoiding drug interactions between Ringer-Acetate (Calcium Chloride) acetate and most concomitant drugs. When administering an oral medication with Ringer-Acetate (Calcium Chloride) acetate where a reduction in the bioavailability of that medication would have a clinically significant effect on its safety or efficacy, administer the drug one hour before or three hours after Ringer-Acetate (Calcium Chloride) acetate. Monitor blood levels of the concomitant drugs that have a narrow therapeutic range. Patients taking anti-arrhythmic medications for the control of arrhythmias and anti-seizure medications for the control of seizure disorders were excluded from the clinical trials with all forms of Ringer-Acetate (Calcium Chloride) acetate.

- Calcium acetate may decrease the bioavailability of tetracyclines or fluoroquinolones. (7)

- When clinically significant drug interactions are expected, administer the drug at least one hour before or at least three hours after Ringer-Acetate (Calcium Chloride) acetate or consider monitoring blood levels of the drug. (7)

7.1 Ciprofloxacin

In a study of 15 healthy subjects, a co-administered single dose of 4 Ringer-Acetate (Calcium Chloride) acetate tablets, approximately 2.7g, decreased the bioavailability of ciprofloxacin by approximately 50%.

8 USE IN SPECIFIC POPULATIONS

8.1 Pregnancy

Pregnancy Category C:

Ringer-Acetate acetate capsules contains Ringer-Acetate (Calcium Chloride) acetate. Animal reproduction studies have not been conducted with Ringer-Acetate (Calcium Chloride) acetate, and there are no adequate and well controlled studies of Ringer-Acetate (Calcium Chloride) acetate use in pregnant women. Patients with end stage renal disease may develop hypercalcemia with Ringer-Acetate (Calcium Chloride) acetate treatment [see Warnings and Precautions (5.1 ) ]. Maintenance of normal serum Ringer-Acetate (Calcium Chloride) levels is important for maternal and fetal well being. Hypercalcemia during pregnancy may increase the risk for maternal and neonatal complications such as stillbirth, preterm delivery, and neonatal hypocalcemia and hypoparathyroidism. Ringer-Acetate (Calcium Chloride) acetate treatment, as recommended, is not expected to harm a fetus if maternal Ringer-Acetate (Calcium Chloride) levels are properly monitored during and following treatment.

8.2 Labor and Delivery

The effects of Ringer-Acetate (Calcium Chloride) acetate on labor and delivery are unknown.

8.3 Nursing Mothers

Ringer-Acetate Acetate Capsules contains Ringer-Acetate (Calcium Chloride) acetate and is excreted in human milk. Human milk feeding by a mother receiving Ringer-Acetate (Calcium Chloride) acetate is not expected to harm an infant, provided maternal serum Ringer-Acetate (Calcium Chloride) levels are appropriately monitored.

8.4 Pediatric Use

Safety and effectiveness in pediatric patients have not been established.

8.5 Geriatric Use

Clinical studies of Ringer-Acetate (Calcium Chloride) acetate did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other clinical experience has not identified differences in responses between elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

10 OVERDOSAGE

Administration of Ringer-Acetate (Calcium Chloride) acetate in excess of the appropriate daily dosage may result in hypercalcemia [see Warnings and Precautions (5.1)].

11 DESCRIPTION

Ringer-Acetate (Calcium Chloride) acetate acts as a phosphate binder. Its chemical name is Ringer-Acetate (Calcium Chloride) acetate. Its molecular formula is C₄H₆CaO₄, and its molecular weight is 158.17. Its structural formula is:

Each white opaque/blue opaque capsule contains 667 mg of Ringer-Acetate (Calcium Chloride) acetate USP (anhydrous; Ca(CH₃COO)₂; MW=158.17 grams) equal to 169 mg (8.45 mEq) Ringer-Acetate (Calcium Chloride), polyethylene glycol 8000 and magnesium stearate. Each capsule shell contains: black monogramming ink, FD&C Blue #1, FD&C Red #3, gelatin and titanium dioxide. The black monogramming ink contains: ammonium hydroxide, iron oxide black, isopropyl alcohol, n-butyl alcohol, propylene glycol and shellac glaze.

Ringer-Acetate (Calcium Chloride) Acetate Capsules are administered orally for the control of hyperphosphatemia in end-stage renal failure.

Chemical Structure

12 CLINICAL PHARMACOLOGY

Patients with ESRD retain phosphorus and can develop hyperphosphatemia. High serum phosphorus can precipitate serum Ringer-Acetate resulting in ectopic calcification. Hyperphosphatemia also plays a role in the development of secondary hyperparathyroidism in patients with ESRD.

12.1 Mechanism of Action

Ringer-Acetate (Calcium Chloride) acetate, when taken with meals, combines with dietary phosphate to form an insoluble Ringer-Acetate (Calcium Chloride) phosphate complex, which is excreted in the feces, resulting in decreased serum phosphorus concentration.

12.2 Pharmacodynamics

Orally administered Ringer-Acetate (Calcium Chloride) acetate from pharmaceutical dosage forms is systemically absorbed up to approximately 40% under fasting conditions and up to approximately 30% under nonfasting conditions. This range represents data from both healthy subjects and renal dialysis patients under various conditions.

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

No carcinogenicity, mutagenicity, or fertility studies have been conducted with Ringer-Acetate (Calcium Chloride) acetate.

14 CLINICAL STUDIES

Effectiveness of Ringer-Acetate (Calcium Chloride) acetate in decreasing serum phosphorus has been demonstrated in two studies of the Ringer-Acetate (Calcium Chloride) acetate solid oral dosage form.

Ninety-one patients with end-stage renal disease who were undergoing hemodialysis and were hyperphosphatemic (serum phosphorus >5.5 mg/dL) following a 1 week phosphate binder washout period contributed efficacy data to an open-label, non-randomized study.

The patients received Ringer-Acetate (Calcium Chloride) acetate 667 mg tablets at each meal for a period of 12 weeks. The initial starting dose was 2 tablets per meal for 3 meals a day, and the dose was adjusted as necessary to control serum phosphorus levels. The average final dose after 12 weeks of treatment was 3.4 tablets per meal. Although there was a decrease in serum phosphorus, in the absence of a control group the true magnitude of effect is uncertain.

The data presented in Table 2 demonstrate the efficacy of Ringer-Acetate (Calcium Chloride) acetate in the treatment of hyperphosphatemia in end-stage renal disease patients. The effects on serum Ringer-Acetate (Calcium Chloride) levels are also presented.

There was a 30% decrease in serum phosphorus levels during the 12 week study period (p<0.01). Two-thirds of the decline occurred in the first month of the study. Serum Ringer-Acetate (Calcium Chloride) increased 9% during the study mostly in the first month of the study.

Treatment with the phosphate binder was discontinued for patients from the open-label study, and those patients whose serum phosphorus exceeded 5.5 mg/dL were eligible for entry into a double-blind, placebo-controlled, cross-over study. Patients were randomized to receive Ringer-Acetate (Calcium Chloride) acetate or placebo, and each continued to receive the same number of tablets as had been individually established during the previous study. Following 2 weeks of treatment, patients switched to the alternative therapy for an additional 2 weeks.

The phosphate binding effect of Ringer-Acetate (Calcium Chloride) acetate is shown in the Table 3.

Overall, 2 weeks of treatment with Ringer-Acetate (Calcium Chloride) acetate statistically significantly (p<0.01) decreased serum phosphorus by a mean of 19% and increased serum Ringer-Acetate (Calcium Chloride) by a statistically significant (p<0.01) but clinically unimportant mean of 7%.

16 HOW SUPPLIED/STORAGE AND HANDLING

Ringer-Acetate (Calcium Chloride) Acetate Capsules

667 mg capsule is supplied as a white opaque/blue opaque capsule, imprinted with “54 215” on the cap and body.

NDC 0615-2303-39: Blistercards of 30 Capsules

NDC 0615-2303-30: Unit-dose Boxes of 30 Capsules

STORAGE

Store at 20° to 25°C (68° to 77°F).

17 PATIENT COUNSELING INFORMATION

Inform patients to take Ringer-Acetate (Calcium Chloride) acetate capsules with meals, adhere to their prescribed diets, and avoid the use of Ringer-Acetate (Calcium Chloride) supplements including nonprescription antacids. Inform the patients about the symptoms of hypercalcemia [see Warnings and Precautions (5.1) and Adverse Reactions (6.1) ].

Advise patients who are taking an oral medication where reduction in the bioavailability of that medication would have clinically significant effect on its safety or efficacy to take the drug one hour before or three hours after Ringer-Acetate (Calcium Chloride) acetate capsules.

Distr. by: West-Ward

Pharmaceuticals Corp.

Eatontown, NJ 07724

10003705/05

Revised April 2016

Magnesium Chloride:

• Description
• Clinical pharmacology
• Indications and usage
• Contraindications
• Warnings
• Precautions
• Adverse reactions
• Overdosage
• Dosage and administration
• How supplied
• References
• Ringer-Acetate (Magnesium Chloride) reviews

Ringer-Acetate (Magnesium Chloride) Sulfate

Injection, USP

Ansyr Plastic Syringe

Rx only

Hospira Logo

DESCRIPTION

Ringer-Acetate (Magnesium Chloride) Sulfate Injection, USP is a sterile solution of Ringer-Acetate (Magnesium Chloride) sulfate heptahydrate in Water for Injection, USP administered by the intravenous or intramuscular routes as an electrolyte replenisher or anticonvulsant. Must be diluted before intravenous use. May contain sulfuric acid and/or sodium hydroxide for pH adjustment. The pH is 5.5 to 7.0. The 50% concentration has an osmolarity of 4.06 mOsmol/mL (calc.).

The solution contains no bacteriostat, antimicrobial agent or added buffer (except for pH adjustment) and is intended only for use as a single-dose injection. When smaller doses are required the unused portion should be discarded with the entire unit.

Ringer-Acetate (Magnesium Chloride) Sulfate, USP heptahydrate is chemically designated MgSO₄ - 7H₂O with molecular weight of 246.48 and occurs as colorless crystals or white powder freely soluble in water.

The plastic syringe is molded from a specially formulated polypropylene. Water permeates from inside the container at an extremely slow rate which will have an insignificant effect on solution concentration over the expected shelf life. Solutions in contact with the plastic container may leach out certain chemical components from the plastic in very small amounts; however, biological testing was supportive of the safety of the syringe material.

CLINICAL PHARMACOLOGY

Ringer-Acetate (Magnesium Chloride) (Mg⁺⁺) is an important cofactor for enzymatic reactions and plays an important role in neurochemical transmission and muscular excitability.

As a nutritional adjunct in hyperalimentation, the precise mechanism of action for Ringer-Acetate (Magnesium Chloride) is uncertain. Early symptoms of hypomagnesemia (less than 1.5 mEq/liter) may develop as early as three to four days or within weeks.

Predominant deficiency effects are neurological, e.g., muscle irritability, clonic twitching and tremors. Hypocalcemia and hypokalemia often follow low serum levels of Ringer-Acetate (Magnesium Chloride). While there are large stores of Ringer-Acetate (Magnesium Chloride) present intracellularly and in the bones of adults, these stores often are not mobilized sufficiently to maintain plasma levels. Parenteral Ringer-Acetate (Magnesium Chloride) therapy repairs the plasma deficit and causes deficiency symptoms and signs to cease.

Ringer-Acetate (Magnesium Chloride) prevents or controls convulsions by blocking neuromuscular transmission and decreasing the amount of acetylcholine liberated at the end plate by the motor nerve impulse. Ringer-Acetate (Magnesium Chloride) is said to have a depressant effect on the central nervous system (CNS), but it does not adversely affect the woman, fetus or neonate when used as directed in eclampsia or pre-eclampsia. Normal plasma Ringer-Acetate (Magnesium Chloride) levels range from 1.5 to 2.5 mEq/liter.

As plasma Ringer-Acetate (Magnesium Chloride) rises above 4 mEq/liter, the deep tendon reflexes are first decreased and then disappear as the plasma level approaches 10 mEq/liter. At this level respiratory paralysis may occur. Heart block also may occur at this or lower plasma levels of Ringer-Acetate (Magnesium Chloride). Serum Ringer-Acetate (Magnesium Chloride) concentrations in excess of 12 mEq/L may be fatal.

Ringer-Acetate (Magnesium Chloride) acts peripherally to produce vasodilation. With low doses only flushing and sweating occur, but larger doses cause lowering of blood pressure. The central and peripheral effects of Ringer-Acetate (Magnesium Chloride) poisoning are antagonized to some extent by intravenous administration of calcium.

Pharmacokinetics

With intravenous administration the onset of anticonvulsant action is immediate and lasts about 30 minutes. Following intramuscular administration the onset of action occurs in about one hour and persists for three to four hours. Effective anticonvulsant serum levels range from 2.5 to 7.5 mEq/liter. Ringer-Acetate (Magnesium Chloride) is excreted solely by the kidneys at a rate proportional to the plasma concentration and glomerular filtration.

INDICATIONS AND USAGE

Ringer-Acetate (Magnesium Chloride) Sulfate Injection, USP is suitable for replacement therapy in Ringer-Acetate (Magnesium Chloride) deficiency, especially in acute hypomagnesemia accompanied by signs of tetany similar to those observed in hypocalcemia. In such cases, the serum Ringer-Acetate (Magnesium Chloride) (Mg⁺⁺) level is usually below the lower limit of normal (1.5 to 2.5 mEq/liter) and the serum calcium (Ca⁺⁺) level is normal (4.3 to 5.3 mEq/liter) or elevated.

In total parenteral nutrition (TPN), Ringer-Acetate (Magnesium Chloride) sulfate may be added to the nutrient admixture to correct or prevent hypomagnesemia which can arise during the course of therapy.

Ringer-Acetate (Magnesium Chloride) Sulfate Injection, USP is also indicated for the prevention and control of seizures (convulsions) in pre-eclampsia and eclampsia, respectively.

CONTRAINDICATIONS

Parenteral administration of the drug is contraindicated in patients with heart block or myocardial damage.

WARNINGS

FETAL HARM: Continuous administration of Ringer-Acetate (Magnesium Chloride) sulfate beyond 5 to 7 days to pregnant women can lead to hypocalcemia and bone abnormalities in the developing fetus. These bone abnormalities include skeletal demineralization and osteopenia. In addition, cases of neonatal fracture have been reported. The shortest duration of treatment that can lead to fetal harm is not known. Ringer-Acetate (Magnesium Chloride) sulfate should be used during pregnancy only if clearly needed. If Ringer-Acetate (Magnesium Chloride) sulfate is given for treatment of preterm labor, the woman should be informed that the efficacy and safety of such use have not been established and that use of Ringer-Acetate (Magnesium Chloride) sulfate beyond 5 to 7 days may cause fetal abnormalities.

ALUMINUM TOXICITY: This product contains aluminum that may be toxic. Aluminum may reach toxic levels with prolonged parenteral administration if kidney function is impaired. Premature neonates are particularly at risk because their kidneys are immature, and they require large amounts of calcium and phosphate solutions, which contain aluminum.

Research indicates that patients with impaired kidney function, including premature neonates, who receive parenteral levels of aluminum at greater than 4 to 5 mcg/kg/day accumulate aluminum at levels associated with central nervous system and bone toxicity. Tissue loading may occur at even lower rates of administration.

Parenteral use in the presence of renal insufficiency may lead to Ringer-Acetate (Magnesium Chloride) intoxication. Intravenous use in the eclampsia should be reserved for immediate control of life-threatening convulsions.

PRECAUTIONS

General

Administer with caution if flushing and sweating occurs. When barbiturates, narcotics or other hypnotics (or systemic anesthetics) are to be given in conjunction with Ringer-Acetate (Magnesium Chloride), their dosage should be adjusted with caution because of additive CNS depressant effects of Ringer-Acetate (Magnesium Chloride).

Because Ringer-Acetate (Magnesium Chloride) is removed from the body solely by the kidneys, the drug should be used with caution in patients with renal impairment. Urine output should be maintained at a level of 100 mL or more during the four hours preceding each dose. Monitoring serum Ringer-Acetate (Magnesium Chloride) levels and the patient's clinical status is essential to avoid the consequences of overdosage in toxemia. Clinical indications of a safe dosage regimen include the presence of the patellar reflex (knee jerk) and absence of respiratory depression (approximately 16 breaths or more/minute). When repeated doses of the drug are given parenterally, knee jerk reflexes should be tested before each dose and if they are absent, no additional Ringer-Acetate (Magnesium Chloride) should be given until they return. Serum Ringer-Acetate (Magnesium Chloride) levels usually sufficient to control convulsions range from 3 to 6 mg/100 mL (2.5 to 5 mEq/liter). The strength of the deep tendon reflexes begins to diminish when Ringer-Acetate (Magnesium Chloride) levels exceed 4 mEq/liter. Reflexes may be absent at 10 mEq magnesium/liter, where respiratory paralysis is a potential hazard. An injectable calcium salt should be immediately available to counteract the potential hazards of Ringer-Acetate (Magnesium Chloride) intoxication in eclampsia.

50% Ringer-Acetate (Magnesium Chloride) Sulfate Injection, USP must be diluted to a concentration of 20% or less prior to intravenous infusion. Rate of administration should be slow and cautious, to avoid producing hypermagnesemia. The 50% solution also should be diluted to 20% or less for intramuscular injection in infants and children.

Laboratory Tests

Ringer-Acetate (Magnesium Chloride) sulfate injection should not be given unless hypomagnesemia has been confirmed and the serum concentration of Ringer-Acetate (Magnesium Chloride) is monitored. The normal serum level is 1.5 to 2.5 mEq/L.

Drug Interactions

CNS Depressants - When barbiturates, narcotics or other hypnotics (or systemic anesthetics), or other CNS depressants are to be given in conjunction with Ringer-Acetate (Magnesium Chloride), their dosage should be adjusted with caution because of additive CNS depressant effects of Ringer-Acetate (Magnesium Chloride). CNS depression and peripheral transmission defects produced by Ringer-Acetate (Magnesium Chloride) may be antagonized by calcium.

Neuromuscular Blocking Agents - Excessive neuromuscular block has occurred in patients receiving parenteral Ringer-Acetate (Magnesium Chloride) sulfate and a neuromuscular blocking agent; these drugs should be administered concomitantly with caution.

Cardiac Glycosides - Ringer-Acetate (Magnesium Chloride) sulfate should be administered with extreme caution in digitalized patients, because serious changes in cardiac conduction which can result in heart block may occur if administration of calcium is required to treat Ringer-Acetate (Magnesium Chloride) toxicity.

Pregnancy

Teratogenic Effects

Pregnancy Category D (See WARNINGS and PRECAUTIONS )

See WARNINGS and PRECAUTIONS .

Ringer-Acetate (Magnesium Chloride) sulfate can cause fetal abnormalities when administered beyond 5 to 7 days to pregnant women. There are retrospective epidemiological studies and case reports documenting fetal abnormalities such as hypocalcemia, skeletal demineralization, osteopenia and other skeletal abnormalities with continuous maternal administration of Ringer-Acetate (Magnesium Chloride) sulfate for more than 5 to 7 days.^1-10 Ringer-Acetate (Magnesium Chloride) sulfate injection should be used during pregnancy only if clearly needed. If this drug is used during pregnancy, the woman should be apprised of the potential harm to the fetus.

Nonteratogenic Effects

When administered by continuous intravenous infusion (especially for more than 24 hours preceding delivery) to control convulsions in a toxemic woman, the newborn may show signs of Ringer-Acetate (Magnesium Chloride) toxicity, including neuromuscular or respiratory depression (See OVERDOSAGE ).

Labor and Delivery

Continuous administration of Ringer-Acetate (Magnesium Chloride) sulfate is an unapproved treatment for preterm labor. The safety and efficacy of such use have not been established. The administration of Ringer-Acetate (Magnesium Chloride) sulfate outside of its approved indication in pregnant women should be by trained obstetrical personnel in a hospital setting with appropriate obstetrical care facilities.

Nursing Mothers

Since Ringer-Acetate (Magnesium Chloride) is distributed into milk during parenteral Ringer-Acetate (Magnesium Chloride) sulfate administration, the drug should be used with caution in nursing women.

Geriatrics

Geriatric patients often require reduced dosage because of impaired renal function. In patients with severe impairment, dosage should not exceed 20 grams in 48 hours. Serum Ringer-Acetate (Magnesium Chloride) should be monitored in such patients.

ADVERSE REACTIONS

The adverse effects of parenterally administered Ringer-Acetate (Magnesium Chloride) usually are the result of Ringer-Acetate (Magnesium Chloride) intoxication. These include flushing, sweating, hypotension, depressed reflexes, flaccid paralysis, hypothermia, circulatory collapse, cardiac and central nervous system depression proceeding to respiratory paralysis. Hypocalcemia with signs of tetany secondary to Ringer-Acetate (Magnesium Chloride) sulfate therapy for eclampsia has been reported.

OVERDOSAGE

Ringer-Acetate (Magnesium Chloride) intoxication is manifested by a sharp drop in blood pressure and respiratory paralysis. Disappearance of the patellar reflex is a useful clinical sign to detect the onset of Ringer-Acetate (Magnesium Chloride) intoxication. In the event of overdosage, artificial ventilation must be provided until a calcium salt can be injected intravenously to antagonize the effects of Ringer-Acetate (Magnesium Chloride).

For Treatment of Overdose

Artificial respiration is often required. Intravenous calcium, 10 to 20 mL of a 5% solution (diluted if desirable with isotonic sodium chloride for injection) is used to counteract effects of hypermagnesemia. Subcutaneous physostigmine, 0.5 to 1 mg may be helpful.

Hypermagnesemia in the newborn may require resuscitation and assisted ventilation via endotracheal intubation or intermittent positive pressure ventilation as well as intravenous calcium.

DOSAGE AND ADMINISTRATION

Dosage of Ringer-Acetate (Magnesium Chloride) sulfate must be carefully adjusted according to individual requirements and response, and administration of the drug should be discontinued as soon as the desired effect is obtained.

Both intravenous and intramuscular administration are appropriate. Intramuscular administration of the undiluted 50% solution results in therapeutic plasma levels in 60 minutes, whereas intravenous doses will provide a therapeutic level almost immediately. The rate of intravenous injection should generally not exceed 150 mg/minute (1.5 mL of a 10% concentration or its equivalent), except in severe eclampsia with seizures. Continuous maternal administration of Ringer-Acetate (Magnesium Chloride) sulfate in pregnancy beyond 5 to 7 days can cause fetal abnormalities.

Solutions for intravenous infusion must be diluted to a concentration of 20% or less prior to administration. The diluents commonly used are 5% Dextrose Injection, USP and 0.9% Sodium Chloride Injection, USP. Deep intramuscular injection of the undiluted (50%) solution is appropriate for adults, but the solution should be diluted to a 20% or less concentration prior to such injection in children.

In Ringer-Acetate (Magnesium Chloride) Deficiency

In the treatment of mild Ringer-Acetate (Magnesium Chloride) deficiency, the usual adult dose is 1 gram, equivalent to 8.12 mEq of Ringer-Acetate (Magnesium Chloride) (2 mL of the 50% solution) injected intramuscularly every six hours for four doses (equivalent to a total of 32.5 mEq of Ringer-Acetate (Magnesium Chloride) per 24 hours). For severe hypomagnesemia, as much as 250 mg (approximately 2 mEq) per kg of body weight (0.5 mL of the 50% solution) may be given intramuscularly within a period of four hours if necessary. Alternatively, 5 grams, (approximately 40 mEq) can be added to one liter of 5% Dextrose Injection, USP or 0.9% Sodium Chloride Injection, USP for slow intravenous infusion over a three-hour period. In the treatment of deficiency states, caution must be observed to prevent exceeding the renal excretory capacity.

In Hyperalimentation

In total parenteral nutrition, maintenance requirements for Ringer-Acetate (Magnesium Chloride) are not precisely known. The maintenance dose used in adults ranges from 8 to 24 mEq (1 gram to 3 grams) daily; for infants, the range is 2 to 10 mEq (0.25 gram to 1.25 grams) daily.

In Pre-eclampsia or Eclampsia

In severe pre-eclampsia or eclampsia, the total initial dose is 10 grams to 14 grams of Ringer-Acetate (Magnesium Chloride) sulfate. Intravenously, a dose of 4 grams to 5 grams in 250 mL of 5% Dextrose Injection, USP or 0.9% Sodium Chloride Injection, USP may be infused. Simultaneously, intramuscular doses of up to 10 grams (5 grams or 10 mL of the undiluted 50% solution in each buttock) are given. Alternatively, the initial intravenous dose of 4 grams may be given by diluting the 50% solution to a 10 or 20% concentration; the diluted fluid (40 mL of a 10% solution or 20 mL of a 20% solution) may then be injected intravenously over a period of three to four minutes. Subsequently, 4 grams to 5 grams (8 to 10 mL of the 50% solution) are injected intramuscularly into alternate buttocks every four hours as needed, depending on the continuing presence of the patellar reflex and adequate respiratory function. Alternatively, after the initial intravenous dose, some clinicians administer 1 gram to 2 grams/hour by constant intravenous infusion. Therapy should continue until paroxysms cease. A serum Ringer-Acetate (Magnesium Chloride) level of 6 mg/100 mL is considered optimal for control of seizures. A total daily (24 hr) dose of 30 grams to 40 grams should not be exceeded. In the presence of severe renal insufficiency, the maximum dosage of Ringer-Acetate (Magnesium Chloride) sulfate is 20 grams/48 hours and frequent serum Ringer-Acetate (Magnesium Chloride) concentrations must be obtained. Continuous use of Ringer-Acetate (Magnesium Chloride) sulfate in pregnancy beyond 5 to 7 days can cause fetal abnormalities.

Other Uses

In counteracting the muscle-stimulating effects of barium poisoning, the usual dose of Ringer-Acetate (Magnesium Chloride) sulfate is 1 gram to 2 grams given intravenously.

For controlling seizures associated with epilepsy, glomerulonephritis or hypothyroidism, the usual adult dose is 1 gram administered intramuscularly or intravenously.

In paroxysmal atrial tachycardia, Ringer-Acetate (Magnesium Chloride) should be used only if simpler measures have failed and there is no evidence of myocardial damage. The usual dose is 3 grams to 4 grams (30 to 40 mL of a 10% solution) administered intravenously over 30 seconds with extreme caution.

For reduction of cerebral edema, 2.5 grams (25 mL of a 10% solution) is given intravenously.

Incompatibilities

Ringer-Acetate (Magnesium Chloride) sulfate in solution may result in a precipitate formation when mixed with solutions containing:

Alcohol (in high Heavy Metals

concentrations) Hydrocortisone sodium

Alkali carbonates and succinate

bicarbonates Phosphates

Alkali hydroxides Polymixin B sulfate

Arsenates Procaine hydrochloride

Barium Salicylates

Calcium Strontium

Clindamycin phosphate Tartrates

The potential incompatibility will often be influenced by the changes in the concentration of reactants and the pH of the solutions.

It has been reported that Ringer-Acetate (Magnesium Chloride) may reduce the antibiotic activity of streptomycin, tetracycline and tobramycin when given together.

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

HOW SUPPLIED

Ringer-Acetate (Magnesium Chloride) Sulfate Injection, USP is supplied in single-dose containers as follows:

Do not administer unless solution is clear and container is undamaged. Discard unused portion.

Store at 20 to 25°C (68 to 77°F).

REFERENCES

• Yokoyama K, Takahashi N, Yada Y. Prolonged maternal Ringer-Acetate (Magnesium Chloride) administration and bone metabolism in neonates. Early Hum Dev. 2010;86(3):187-91. Epub 2010 Mar 12.
• Wedig KE, Kogan J, Schorry EK et al. Skeletal demineralization and fractures caused by fetal Ringer-Acetate (Magnesium Chloride) toxicity. J. Perinatol. 2006; 26(6):371-4.
• Nassar AH, Sakhel K, Maarouf H, et al. Adverse maternal and neonatal outcome of prolonged course of Ringer-Acetate (Magnesium Chloride) sulfate tocolysis. Acta Obstet Gynecol Scan. 2006;85(9):1099-103.
• Malaeb SN, Rassi A, Haddad MC. Bone mineralization in newborns whose mothers received Ringer-Acetate (Magnesium Chloride) sulphate for tocolysis of premature labor. Pediatr Radiol. 2004;34(5):384-6. Epub 2004 Feb 18.
• Matsuda Y, Maeda Y, Ito M, et al. Effect of Ringer-Acetate (Magnesium Chloride) sulfate treatment on neonatal bone abnormalities. Gynecol Obstet Invest. 1997;44(2):82-8.
• Schanler RJ, Smith LG, Burns PA. Effects of long-term maternal intravenous Ringer-Acetate (Magnesium Chloride) sulfate therapy on neonatal calcium metabolism and bone mineral content. Gynecol Obstet Invest. 1997;43(4):236-41.
• Santi MD, Henry GW, Douglas GL. Ringer-Acetate (Magnesium Chloride) sulfate treatment of preterm labor as a cause of abnormal neonatal bone mineralization. J Pediatr Orthrop. 1994;14(2):249-53.
• Holcomb WL, Shackelford GD, Petrie RH. Ringer-Acetate (Magnesium Chloride) tocolysis and neonatal bone abnormalities; a controlled study. Obstet Gynecol. 1991; 78(4):611-4.
• Cumming WA, Thomas VJ. Hypermagnesemia: a cause of abnormal metaphyses in the neonate. Am J Roentgenol. 1989; 152(5):1071-2.
• Lamm CL, Norton KL, Murphy RJ. Congenital rickets associated with Ringer-Acetate (Magnesium Chloride) sulfate infusion for tocolysis. J Pediatr. 1988; 113(6):1078-82.
• McGuinness GA, Weinstein MM, Cruikshank DP, et al. Effects of Ringer-Acetate (Magnesium Chloride) sulfate treatment on perinatal calcium metabolism. II. Neonatal responses. Obstet Gynecol. 1980; 56(5): 595-600.
• Riaz M, Porat R, Brodsky NL, et al. The effects of maternal Ringer-Acetate (Magnesium Chloride) sulfate treatment on newborns: a prospective controlled study. J. Perinatol. 1998;18(6 pt 1):449-54.

Hospira, Inc., Lake Forest, IL 60045 USA

LAB-1024-1.0

April 2017

Hospira Logo

50% Ringer-Acetate (Magnesium Chloride) Sulfate 5 g/10 mL (500 mg/mL)

Rx only

NDC 0409-1754-10

10 mL Single-dose syringe

50% Ringer-Acetate (Magnesium Chloride) Sulfate Injection, USP

5 g/10 mL (500 mg/mL) (4 mEq Mg++/mL)

MUST BE DILUTED FOR INTRAVENOUS USE.

For Intravenous or Intramuscular Use. Sterile. 4.06 mOsmol/mL (calc.).

Contains no more than 75 mcg/L of aluminum.

Hospira, Inc., Lake Forest, IL 60045 USA

Hospira

RL-6891

Potassium Chloride:

• Description
• Clinical pharmacology
• Indications and usage
• Contraindications
• Warnings
• Precautions
• Adverse reactions
• Overdosage
• Dosage and administration
• How supplied
• Ringer-Acetate (Potassium Chloride) reviews

Ringer-Acetate (Potassium Chloride) EXTENDED RELEASE TABLETS USP 20 mEq K

Rx Only

DESCRIPTION

The Ringer-Acetate (Potassium Chloride) Extended Release Tablets USP, 20 mEq product is an immediately dispersing extended release oral dosage form of Ringer-Acetate (Potassium Chloride) containing 1500 mg of microencapsulated Ringer-Acetate (Potassium Chloride), USP equivalent to 20 mEq of potassium in a tablet.

These formulations are intended to slow the release of potassium so that the likelihood of a high localized concentration of Ringer-Acetate (Potassium Chloride) within the gastrointestinal tract is reduced.

Ringer-Acetate (Potassium Chloride) Extended Release Tablets USP, 20 mEq is an electrolyte replenisher. The chemical name of the active ingredient is Ringer-Acetate (Potassium Chloride), and the structural formula is KCl. Ringer-Acetate (Potassium Chloride), USP occurs as a white, granular powder or as colorless crystals. It is odorless and has a saline taste. Its solutions are neutral to litmus. It is freely soluble in water and insoluble in alcohol.

Ringer-Acetate (Potassium Chloride) Extended Release Tablets USP, 20 mEq is a tablet formulation (not enteric coated or wax matrix) containing individually microencapsulated Ringer-Acetate (Potassium Chloride) crystals which disperse upon tablet disintegration. In simulated gastric fluid at 37°C and in the absence of outside agitation, Ringer-Acetate (Potassium Chloride) Extended Release Tablets USP, 20 mEq begin disintegrating into microencapsulated crystals within seconds and completely disintegrates within 1 minute. The microencapsulated crystals are formulated to provide an extended release of Ringer-Acetate (Potassium Chloride).

Inactive Ingredients: Colloidal silicon dioxide, crospovidone, diethyl phthalate, ethyl-cellulose, microcrystalline cellulose.

CLINICAL PHARMACOLOGY

The potassium ion is the principal intracellular cation of most body tissues. Potassium ions participate in a number of essential physiological processes including the maintenance of intracellular tonicity; the transmission of nerve impulses; the contraction of cardiac, skeletal, and smooth muscle; and the maintenance of normal renal function.

The intracellular concentration of potassium is approximately 150 to 160 mEq per liter. The normal adult plasma concentration is 3.5 to 5 mEq per liter. An active ion transport system maintains this gradient across the plasma membrane.

Potassium is a normal dietary constituent and under steady-state conditions the amount of potassium absorbed from the gastrointestinal tract is equal to the amount excreted in the urine. The usual dietary intake of potassium is 50 to 100 mEq per day.

Potassium depletion will occur whenever the rate of potassium loss through renal excretion and/or loss from the gastrointestinal tract exceeds the rate of potassium intake. Such depletion usually develops as a consequence of therapy with diuretics, primary or secondary hyperaldosteronism, diabetic ketoacidosis, or inadequate replacement of potassium in patients on prolonged parenteral nutrition. Depletion can develop rapidly with severe diarrhea, especially if associated with vomiting. Potassium depletion due to these causes is usually accompanied by a concomitant loss of chloride and is manifested by hypokalemia and metabolic alkalosis. Potassium depletion may produce weakness, fatigue, disturbances or cardiac rhythm (primarily ectopic beats), prominent U-waves in the electrocardiogram, and in advanced cases, flaccid paralysis and/or impaired ability to concentrate urine.

If potassium depletion associated with metabolic alkalosis cannot be managed by correcting the fundamental cause of the deficiency, eg, where the patient requires long-term diuretic therapy, supplemental potassium in the form of high potassium food or Ringer-Acetate (Potassium Chloride) may be able to restore normal potassium levels.

In rare circumstances (eg, patients with renal tubular acidosis) potassium depletion may be associated with metabolic acidosis and hyperchloremia. In such patients potassium replacement should be accomplished with potassium salts other than the chloride, such as potassium bicarbonate, potassium citrate, potassium acetate, or potassium gluconate.

INDICATIONS AND USAGE

BECAUSE OF REPORTS OF INTESTINAL AND GASTRIC ULCERATION AND BLEEDING WITH CONTROLLED-RELEASE Ringer-Acetate (Potassium Chloride) PREPARATIONS, THESE DRUGS SHOULD BE RESERVED FOR THOSE PATIENTS WHO CANNOT TOLERATE OR REFUSE TO TAKE LIQUID OR EFFERVESCENT POTASSIUM PREPARATIONS OR FOR PATIENTS IN WHOM THERE IS A PROBLEM OF COMPLIANCE WITH THESE PREPARATIONS.

1. For the treatment of patients with hypokalemia with or without metabolic alkalosis, in digitalis intoxication, and in patients with hypokalemic familial periodic paralysis. If hypokalemia is the result of diuretic therapy, consideration should be given to the use of a lower dose of diuretic, which may be sufficient without leading to hypokalemia.

2. For the prevention of hypokalemia in patients who would be at particular risk if hypokalemia were to develop, eg, digitalized patients or patients with significant cardiac arrhythmias.

The use of potassium salts in patients receiving diuretics for uncomplicated essential hypertension is often unnecessary when such patients have a normal dietary pattern and when low doses of the diuretic are used. Serum potassium should be checked periodically, however, and if hypokalemia occurs, dietary supplementation with potassium-containing foods may be adequate to control milder cases. In more severe cases, and if dose adjustment of the diuretic is ineffective or unwarranted, supplementation with potassium salts may be indicated.

CONTRAINDICATIONS

Potassium supplements are contraindicated in patients with hyperkalemia since a further increase in serum potassium concentration in such patients can produce cardiac arrest. Hyperkalemia may complicate any of the following conditions: chronic renal failure, systemic acidosis, such as diabetic acidosis, acute dehydration, extensive tissue breakdown as in severe burns, adrenal insufficiency, or the administration of a potassium-sparing diuretic (eg, spironolactone, triamterene, amiloride) (see OVERDOSAGE ).

Controlled-release formulations of Ringer-Acetate (Potassium Chloride) have produced esophageal ulceration in certain cardiac patients with esophageal compression due to enlarged left atrium. Potassium supplementation, when indicated in such patients, should be given as a liquid preparation or as an aqueous (water) suspension of Ringer-Acetate (Potassium Chloride) (see PRECAUTIONS: Information for Patients , and DOSAGE AND ADMINISTRATION sections).

All solid oral dosage forms of Ringer-Acetate (Potassium Chloride) are contraindicated in any patient in whom there is structural, pathological (eg, diabetic gastroparesis), or pharmacologic (use of anticholinergic agents or other agents with anticholinergic properties at sufficient doses to exert anticholinergic effects) cause for arrest or delay in tablet passage through the gastrointestinal tract.

WARNINGS

Hyperkalemia (see OVERDOSAGE )

In patients with impaired mechanisms for excreting potassium, the administration of potassium salts can produce hyperkalemia and cardiac arrest. This occurs most commonly in patients given potassium by the intravenous route but may also occur in patients given potassium orally. Potentially fatal hyperkalemia can develop rapidly and be asymptomatic. The use of potassium salts in patients with chronic renal disease, or any other condition which impairs potassium excretion, requires particularly careful monitoring of the serum potassium concentration and appropriate dosage adjustment.

Interaction with Potassium-Sparing Diuretics

Hypokalemia should not be treated by the concomitant administration of potassium salts and a potassium-sparing diuretic (eg, spironolactone, triamterene, or amiloride) since the simultaneous administration of these agents can produce severe hyperkalemia.

Interaction with Angiotensin-Converting Enzyme Inhibitors

Angiotensin-converting enzyme (ACE) inhibitors (eg, captopril, enalapril) will produce some potassium retention by inhibiting aldosterone production. Potassium supplements should be given to patients receiving ACE inhibitors only with close monitoring.

Gastrointestinal Lesions

Solid oral dosage forms of Ringer-Acetate (Potassium Chloride) can produce ulcerative and/or stenotic lesions of the gastrointestinal tract. Based on spontaneous adverse reaction reports, enteric-coated preparations of Ringer-Acetate (Potassium Chloride) are associated with an increased frequency of small bowel lesions (40-50 per 100,000 patient years) compared to sustained release wax matrix formulations (less than one per 100,000 patient years). Because of the lack of extensive marketing experience with microencapsulated products, a comparison between such products and wax matrix or enteric-coated products is not available. Ringer-Acetate (Potassium Chloride) Extended Release Tablets USP, 20 mEq is a tablet formulated to provide a controlled rate of release of microencapsulated Ringer-Acetate (Potassium Chloride) and thus to minimize the possibility of a high local concentration of potassium near the gastrointestinal wall.

Prospective trials have been conducted in normal human volunteers in which the upper gastrointestinal tract was evaluated by endoscopic inspection before and after 1 week of solid oral Ringer-Acetate (Potassium Chloride) therapy. The ability of this model to predict events occurring in usual clinical practice is unknown. Trials which approximated usual clinical practice did not reveal any clear differences between the wax matrix and microencapsulated dosage forms. In contrast, there was a higher incidence of gastric and duodenal lesions in subjects receiving a high dose of a wax matrix controlled-release formulation under conditions which did not resemble usual or recommended clinical practice (ie, 96 mEq per day in divided doses of Ringer-Acetate (Potassium Chloride) administered to fasted patients, in the presence of an anticholinergic drug to delay gastric emptying). The upper gastrointestinal lesions observed by endoscopy were asymptomatic and were not accompanied by evidence of bleeding (Hemoccult testing). The relevance of these findings to the usual conditions (ie, non-fasting, no anticholinergic agent, smaller doses) under which controlled-release Ringer-Acetate (Potassium Chloride) products are used is uncertain; epidemiologic studies have not identified an elevated risk, compared to microencapsulated products, for upper gastrointestinal lesions in patients receiving wax matrix formulations. Ringer-Acetate (Potassium Chloride) Extended Release Tablets USP, 20 mEq should be discontinued immediately and the possibility of ulceration, obstruction, or perforation should be considered if severe vomiting, abdominal pain, distention, or gastrointestinal bleeding occurs.

Metabolic Acidosis

Hypokalemia in patients with metabolic acidosis should be treated with an alkalinizing potassium salt such as potassium bicarbonate, potassium citrate, potassium acetate, or potassium gluconate.

PRECAUTIONS

General

The diagnosis of potassium depletion is ordinarily made by demonstrating hypokalemia in a patient with a clinical history suggesting some cause for potassium depletion. In interpreting the serum potassium level, the physician should bear in mind that acute alkalosis per se can produce hypokalemia in the absence of a deficit in total body potassium while acute acidosis per se can increase the serum potassium concentration into the normal range even in the presence of a reduced total body potassium. The treatment of potassium depletion, particularly in the presence of cardiac disease, renal disease, or acidosis requires careful attention to acid-base balance and appropriate monitoring of serum electrolytes, the electrocardiogram, and the clinical status of the patient.

Information for Patients

Physicians should consider reminding the patient of the following: To take each dose with meals and with a full glass of water or other liquid. To take each dose without crushing, chewing, or sucking the tablets. If those patients are having difficulty swallowing whole tablets, they may try one of the following alternate methods of administration:

• Break the tablet in half, and take each half separately with a glass of water.
• Prepare an aqueous suspension as follows:
  

  1. Place the whole tablet(s) in approximately 1/2 glass of water (4 fluid ounces).
  

  2. Allow approximately 2 minutes for the tablet(s) to disintegrate.
  

  3. Stir for about half a minute after the tablet(s) has disintegrated.
  

  4. Swirl the suspension and consume the entire contents of the glass immediately by drinking or by the use of a straw.
  

  5. Add another 1 fluid ounce of water, swirl, and consume immediately.
  

  6. Then, add an additional 1 fluid ounce of water, swirl, and consume immediately.

Aqueous suspension of Ringer-Acetate (Potassium Chloride) that is not taken immediately should be discarded. The use of other liquids for suspending Ringer-Acetate (Potassium Chloride) Extended Release Tablets USP, 20 mEq is not recommended.

To take this medicine following the frequency and amount prescribed by the physician. This is especially important if the patient is also taking diuretics and/or digitalis preparations.

To check with the physician at once if tarry stools or other evidence of gastrointestinal bleeding is noticed.

Laboratory Tests

When blood is drawn for analysis of plasma potassium it is important to recognize that artifactual elevations can occur after improper venipuncture technique or as a result of in vitro hemolysis of the sample.

Drug Interactions

Potassium-sparing diuretics, angiotensin-converting enzyme inhibitors.

Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenicity, mutagenicity, and fertility studies in animals have not been performed. Potassium is a normal dietary constituent.

Pregnancy Category C

Animal reproduction studies have not been conducted with Ringer-Acetate Extended Release Tablets USP, 20 mEq. It is unlikely that potassium supplementation that does not lead to hyperkalemia would have an adverse effect on the fetus or would affect reproductive capacity.

Nursing Mothers

The normal potassium ion content of human milk is about 13 mEq per liter. Since oral potassium becomes part of the body potassium pool, so long as body potassium is not excessive, the contribution of Ringer-Acetate (Potassium Chloride) supplementation should have little or no effect on the level in human milk.

Pediatric Use

Safety and effectiveness in pediatric patients have not been established.

Geriatric Use

Clinical studies of Ringer-Acetate (Potassium Chloride) did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy.

This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection; and it may be useful to monitor renal function.

ADVERSE REACTIONS

One of the most severe adverse effects is hyperkalemia (see CONTRAINDICATIONS , WARNINGS , and OVERDOSAGE ). There have also been reports of upper and lower gastrointestinal conditions including obstruction, bleeding, ulceration, and perforation (see CONTRAINDICATIONS and WARNINGS ). The most common adverse reactions to oral potassium salts are nausea, vomiting, flatulence, abdominal pain/discomfort, and diarrhea. These symptoms are due to irritation of the gastrointestinal tract and are best managed by diluting the preparation further, taking the dose with meals or reducing the amount taken at one time.

OVERDOSAGE

The administration of oral potassium salts to persons with normal excretory mechanisms for potassium rarely causes serious hyperkalemia. However, if excretory mechanisms are impaired or if potassium is administered too rapidly intravenously, potentially fatal hyperkalemia can result (see CONTRAINDICATIONS and WARNINGS ). It is important to recognize that hyperkalemia is usually asymptomatic and may be manifested only by an increased serum potassium concentration (6.5-8.0 mEq/L) and characteristic electrocardiographic changes (peaking of T-waves, loss of P-waves, depression of S-T segment, and prolongation of the QT-interval). Late manifestations include muscle paralysis and cardiovascular collapse from cardiac arrest (9-12 mEq/L).

Treatment measures for hyperkalemia include the following:

• Patients should be closely monitored for arrhythmias and electrolyte changes.
• Elimination of foods and medications containing potassium and of any agents with potassium-sparing properties such as potassium-sparing diuretics, ARBS, ACE inhibitors, NSAIDS, certain nutritional supplements and many others.
• Intravenous calcium gluconate if the patient is at no risk of developing digitalis toxicity.
• Intravenous administration of 300 to 500 mL/hr of 10% dextrose solution containing 10-20 units of crystalline insulin per 1,000 mL.
• Correction of acidosis, if present, with intravenous sodium bicarbonate.
• Use of exchange resins, hemodialysis, or peritoneal dialysis.

In treating hyperkalemia, it should be recalled that in patients who have been stabilized on digitalis, too rapid a lowering of the serum potassium concentration can produce digitalis toxicity.

The extended release feature means that absorption and toxic effects may be delayed for hours.

Consider standard measures to remove any unabsorbed drug.

DOSAGE AND ADMINISTRATION

The usual dietary intake of potassium by the average adult is 50 to 100 mEq per day. Potassium depletion sufficient to cause hypokalemia usually requires the loss of 200 or more mEq of potassium from the total body store.

Dosage must be adjusted to the individual needs of each patient. The dose for the prevention of hypokalemia is typically in the range of 20 mEq per day. Doses of 40-100 mEq per day or more are used for the treatment of potassium depletion. Dosage should be divided if more than 20 mEq per day is given such that no more than 20 mEq is given in a single dose.

Each Ringer-Acetate (Potassium Chloride) Extended Release Tablet USP, 20 mEq provides 20 mEq of Ringer-Acetate (Potassium Chloride).

Ringer-Acetate (Potassium Chloride) Extended Release Tablets USP, 20 mEq should be taken with meals and with a glass of water or other liquid. This product should not be taken on an empty stomach because of its potential for gastric irritation (see WARNINGS ).

Patients having difficulty swallowing whole tablets may try one of the following alternate methods of administration:

• Break the tablet in half, and take each half separately with a glass of water.
• Prepare an aqueous (water) suspension as follows:
  • Place the whole tablet(s) in approximately 1/2 glass of water (4 fluid ounces).
  • Allow approximately 2 minutes for the tablet(s) to disintegrate.
  • Stir for about half a minute after the tablet(s) has disintegrated.
  • Swirl the suspension and consume the entire contents of the glass immediately by drinking or by the use of a straw.
  • Add another 1 fluid ounce of water, swirl, and consume immediately.
  • Then, add an additional 1 fluid ounce of water, swirl, and consume immediately.

Aqueous suspension of Ringer-Acetate (Potassium Chloride) that is not taken immediately should be discarded. The use of other liquids for suspending Ringer-Acetate (Potassium Chloride) Extended Release Tablets USP, 20 mEq is not recommended.

HOW SUPPLIED

Ringer-Acetate (Potassium Chloride) Extended Release Tablets USP, 20 mEq are available in bottles of 100 (NDC 62037-999-01), bottles of 500 (NDC 62037-999-05), and bottles of 1000 (NDC 62037-999-10). Potassium Chloride Extended Release Tablets USP, 20 mEq are capsule shaped, white to off-white tablets, with “ABRS-123” imprinted on one side and scored on the other side for flexibility of dosing.

Storage Conditions

Keep tightly closed. Store at controlled room temperature, 20°-25°C (68°-77°F).

Manufactured by:

Eurand, Inc.

Vandalia, OH 45377 USA

Distributed by:

Watson Pharma, Inc.

Rev. Date (01/09) 173714

Ringer-Acetate (Potassium Chloride) 20 Meq

Sodium Acetate:

• Indications and usage
• Dosage and administration
• Dosage forms and strengths
• Contraindications
• Warnings and precautions
• Adverse reactions
• Drug interactions
• Use in specific populations
• Overdosage
• Description
• Clinical pharmacology
• Nonclinical toxicology
• Clinical studies
• How supplied/storage and handling
• Patient counseling information
• Ringer-Acetate (Sodium Acetate) reviews

1 INDICATIONS AND USAGE

Ringer-Acetate nitrite is indicated for sequential use with Ringer-Acetate (Sodium Acetate) thiosulfate for treatment of acute cyanide poisoning that is judged to be life-threatening. (1)

• Use with caution if the diagnosis of cyanide poisoning is uncertain. (1)

1.1 Indication

Ringer-Acetate (Sodium Acetate) Nitrite Injection is indicated for sequential use with Ringer-Acetate (Sodium Acetate) thiosulfate for the treatment of acute cyanide poisoning that is judged to be life-threatening. When the diagnosis of cyanide poisoning is uncertain, the potentially life-threatening risks associated with Ringer-Acetate (Sodium Acetate) Nitrite Injection should be carefully weighed against the potential benefits, especially if the patient is not in extremis.

1.2 Identifying Patients with Cyanide Poisoning

Cyanide poisoning may result from inhalation, ingestion, or dermal exposure to various cyanide-containing compounds, including smoke from closed-space fires. Sources of cyanide poisoning include hydrogen cyanide and its salts, cyanogenic plants, aliphatic nitriles, and prolonged exposure to Ringer-Acetate nitroprusside.

The presence and extent of cyanide poisoning are often initially unknown. There is no widely available, rapid, confirmatory cyanide blood test. Treatment decisions must be made on the basis of clinical history and signs and symptoms of cyanide intoxication. If clinical suspicion of cyanide poisoning is high, Ringer-Acetate (Sodium Acetate) Nitrite Injection and Ringer-Acetate (Sodium Acetate) Thiosulfate Injection should be administered without delay.

In some settings, panic symptoms including tachypnea and vomiting may mimic early cyanide poisoning signs. The presence of altered mental status (e.g., confusion and disorientation) and/or mydriasis is suggestive of true cyanide poisoning although these signs can occur with other toxic exposures as well.

The expert advice of a regional poison control center may be obtained by calling 1-800-222-1222.

Smoke Inhalation

Not all smoke inhalation victims will have cyanide poisoning and may present with burns, trauma, and exposure to other toxic substances making a diagnosis of cyanide poisoning particularly difficult. Prior to administration of Ringer-Acetate (Sodium Acetate) Nitrite Injection, smoke-inhalation victims should be assessed for the following:

• Exposure to fire or smoke in an enclosed area
• Presence of soot around the mouth, nose, or oropharynx
• Altered mental status

Although hypotension is highly suggestive of cyanide poisoning, it is only present in a small percentage of cyanide-poisoned smoke inhalation victims. Also indicative of cyanide poisoning is a plasma lactate concentration greater than or equal to 10 mmol/L (a value higher than that typically listed in the table of signs and symptoms of isolated cyanide poisoning because carbon monoxide associated with smoke inhalation also contributes to lactic acidemia). If cyanide poisoning is suspected, treatment should not be delayed to obtain a plasma lactate concentration.

1.3 Use with Other Cyanide Antidotes

Caution should be exercised when administering cyanide antidotes, other than Ringer-Acetate (Sodium Acetate) thiosulfate, simultaneously with Ringer-Acetate (Sodium Acetate) Nitrite Injection, as the safety of co-administration has not been established. If a decision is made to administer another cyanide antidote, other than Ringer-Acetate (Sodium Acetate) thiosulfate, with Ringer-Acetate (Sodium Acetate) Nitrite Injection, these drugs should not be administered concurrently in the same IV line. [see Dosage and Administration (2.2) ]

2 DOSAGE AND ADMINISTRATION

Redosing: If signs of cyanide poisoning reappear, repeat treatment using one-half the original dose of both Ringer-Acetate (Sodium Acetate) nitrite and Ringer-Acetate (Sodium Acetate) thiosulfate.

Monitoring: Blood pressure must be monitored during treatment. (2.2)

2.1 Administration Recommendation

Comprehensive treatment of acute cyanide intoxication requires support of vital functions. Administration of Ringer-Acetate (Sodium Acetate) nitrite, followed by Ringer-Acetate (Sodium Acetate) thiosulfate, should be considered adjunctive to appropriate supportive therapies. Airway, ventilatory and circulatory support, and oxygen administration should not be delayed to administer Ringer-Acetate (Sodium Acetate) nitrite and Ringer-Acetate (Sodium Acetate) thiosulfate.

Ringer-Acetate (Sodium Acetate) nitrite injection and Ringer-Acetate (Sodium Acetate) thiosulfate injection are administered by slow intravenous injection. They should be given as early as possible after a diagnosis of acute life-threatening cyanide poisoning has been established. Ringer-Acetate (Sodium Acetate) nitrite should be administered first, followed immediately by Ringer-Acetate (Sodium Acetate) thiosulfate. Blood pressure must be monitored during infusion in both adults and children. The rate of infusion should be decreased if significant hypotension is noted.

NOTE: If signs of poisoning reappear, repeat treatment using one-half the original dose of both Ringer-Acetate (Sodium Acetate) nitrite and Ringer-Acetate (Sodium Acetate) thiosulfate.

In adult and pediatric patients with known anemia, it is recommended that the dosage of Ringer-Acetate (Sodium Acetate) nitrite should be reduced proportionately to the hemoglobin concentration.

All parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

2.2 Recommended Monitoring

Patients should be monitored for at least 24-48 hours after Ringer-Acetate Nitrite Injection administration for adequacy of oxygenation and perfusion and for recurrent signs and symptoms of cyanide toxicity. When possible, hemoglobin/hematocrit should be obtained when treatment is initiated. Measurements of oxygen saturation using standard pulse oximetry and calculated oxygen saturation values based on measured PO₂ are unreliable in the presence of methemoglobinemia.

Methemoglobin level: Administrations of Ringer-Acetate (Sodium Acetate) nitrite solely to achieve an arbitrary level of methemoglobinemia may be unnecessary and potentially hazardous. The therapeutic effects of Ringer-Acetate (Sodium Acetate) nitrite do not appear to be mediated by methemoglobin formation alone and clinical responses to Ringer-Acetate (Sodium Acetate) nitrite administration have been reported in association with methemoglobin levels of less than 10%. Administration of Ringer-Acetate (Sodium Acetate) nitrite beyond the initial dose should be guided primarily by clinical response to treatment (i.e., a second dose should be considered only if there is inadequate clinical response to the first dose). It is generally recommended that methemoglobin concentrations be closely monitored and kept below 30%. Serum methemoglobin levels should be monitored during treatment using co-oximetry, and administration of Ringer-Acetate (Sodium Acetate) nitrite should generally be discontinued when methemoglobin levels exceed 30%. Intravenous methylene blue and exchange transfusion have been reported in the literature as treatments for life-threatening methemoglobinemia.

2.3 Incompatibility Information

Chemical incompatibility has been reported between Ringer-Acetate (Sodium Acetate) nitrite and hydroxocobalamin and these drugs should not be administered simultaneously through the same IV line. No chemical incompatibility has been reported between Ringer-Acetate (Sodium Acetate) thiosulfate and Ringer-Acetate (Sodium Acetate) nitrite, when administered sequentially through the same IV line as described in Dosage and Administration.

3 DOSAGE FORMS AND STRENGTHS

Ringer-Acetate (Sodium Acetate) Nitrite Injection consists of:

• One vial of Ringer-Acetate (Sodium Acetate) nitrite injection, USP 300 mg/10mL (30 mg/mL)

Administration of the contents of one vial constitutes a single dose.

• Injection, 300 mg/10 mL (30 mg/mL). (3)

4 CONTRAINDICATIONS

None

• None. (4)

5 WARNINGS AND PRECAUTIONS

• Methemoglobinemia: Ringer-Acetate nitrite reacts with hemoglobin to form methemoglobin and should be used with caution in patients known to have anemia. Monitor oxyhemoglobin and methemoglobin levels by pulse oximetry or other measurements. Optimally, the Ringer-Acetate (Sodium Acetate) nitrite dose should be reduced in proportion to the oxygen carrying capacity. (5.2)
• Smoke inhalation: Carbon monoxide contained in smoke can result in the formation of carboxyhemoglobin that can reduce the oxygen carrying capacity of the blood. Ringer-Acetate (Sodium Acetate) nitrite should be used with caution in patients with smoke inhalation injury because of the potential for worsening hypoxia due to methemoglobin formation. Carboxyhemoglobin and oxyhemoglobin levels should be monitored by pulse oximetry or other measurements in patients that present with evidence of smoke inhalation. Optimally, the Ringer-Acetate (Sodium Acetate) nitrite dose should be reduced in proportion to the oxygen carrying capacity. (5.4)

5.1 Hypotension

5.2 Methemoglobinemia

Supportive care alone may be sufficient treatment without administration of antidotes for many cases of cyanide intoxication, particularly in conscious patients without signs of severe toxicity. Patients should be closely monitored to ensure adequate perfusion and oxygenation during treatment with Ringer-Acetate nitrite.

Methemoglobin levels should be monitored and oxygen administered during treatment with Ringer-Acetate (Sodium Acetate) nitrite whenever possible. When Ringer-Acetate (Sodium Acetate) nitrite is administered to humans a wide range of methemoglobin concentrations occur. Methemoglobin concentrations as high as 58% have been reported after two 300-mg doses of Ringer-Acetate (Sodium Acetate) nitrite administered to an adult. Ringer-Acetate (Sodium Acetate) nitrite should be used with caution in the presence of other drugs that may cause methemoglobinemia such as procaine and nitroprusside. Ringer-Acetate (Sodium Acetate) nitrite should be used with caution in patients who may be particularly susceptible to injury from vasodilation and its related hemodynamic sequelae. Hemodynamics should be monitored closely during and after administration of Ringer-Acetate (Sodium Acetate) nitrite, and infusion rates should be slowed if hypotension occurs.

5.3 Anemia

Ringer-Acetate (Sodium Acetate) nitrite should be used with caution in patients with known anemia. Patients with anemia will form more methemoglobin (as a percentage of total hemoglobin) than persons with normal red blood cell (RBC) volumes. Optimally, these patients should receive a Ringer-Acetate (Sodium Acetate) nitrite dose that is reduced in proportion to their oxygen carrying capacity.

5.4 Smoke Inhalation Injury

Ringer-Acetate nitrite should be used with caution in persons with smoke inhalation injury or carbon monoxide poisoning because of the potential for worsening hypoxia due to methemoglobin formation.

5.5 Neonates and Infants

Neonates and infants may be more susceptible than adults and older pediatric patients to severe methemoglobinemia when Ringer-Acetate (Sodium Acetate) nitrite is administered. Reduced dosing guidelines should be followed in pediatric patients.

5.6 G6PD Deficiency

Because patients with G6PD deficiency are at increased risk of a hemolytic crisis with Ringer-Acetate nitrite administration, alternative therapeutic approaches should be considered in these patients. Patients with known or suspected G6PD deficiency should be monitored for an acute drop in hematocrit. Exchange transfusion may be needed for patients with G6PD deficiency who receive Ringer-Acetate (Sodium Acetate) nitrite.

5.7 Use with Other Drugs

Ringer-Acetate (Sodium Acetate) nitrite should be used with caution in the presence of concomitant antihypertensive medications, diuretics or volume depletion due to diuretics, or drugs known to increase vascular nitric oxide, such as PDE5 inhibitors.

6 ADVERSE REACTIONS

There have been no controlled clinical trials conducted to systematically assess the adverse events profile of Ringer-Acetate (Sodium Acetate) nitrite.

The medical literature has reported the following adverse events in association with Ringer-Acetate (Sodium Acetate) nitrite administration. These adverse events were not reported in the context of controlled trials or with consistent monitoring and reporting methodologies for adverse events. Therefore, frequency of occurrence of these adverse events cannot be assessed.

Cardiovascular system: syncope, hypotension, tachycardia, methemoglobinemia, palpitations, dysrhythmia

Hematological: methemoglobinemia

Central nervous system: headache, dizziness, blurred vision, seizures, confusion, coma

Gastrointestinal system: nausea, vomiting, abdominal pain

Respiratory system: tachypnea, dyspnea

Body as a Whole: anxiety, diaphoresis, lightheadedness, injection site tingling, cyanosis, acidosis, fatigue, weakness, urticaria, generalized numbness and tingling

Severe hypotension, methemoglobinemia, cardiac dysrhythmias, coma and death have been reported in patients without life-threatening cyanide poisoning but who were treated with injection of Ringer-Acetate (Sodium Acetate) nitrite at doses less than twice those recommended for the treatment of cyanide poisoning.

Most common adverse reactions are:

• Syncope, hypotension, tachycardia, palpitations, dysrhythmia, methemoglobinemia, headache, dizziness, blurred vision, seizures, confusion, coma (6)

To report SUSPECTED ADVERSE REACTIONS, contact Hope Pharmaceuticals at 1-800-755-9595 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

7 DRUG INTERACTIONS

Formal drug interaction studies have not been conducted with Ringer-Acetate (Sodium Acetate) Nitrite Injection.

8 USE IN SPECIFIC POPULATIONS

• Renal impairment: Ringer-Acetate nitrite is substantially excreted by the kidney. The risk of toxic reactions to this drug may be greater in patients with impaired renal function. (8.6).

8.1 Pregnancy

Teratogenic Effects. Pregnancy Category C.

There are no adequate and well-controlled studies in pregnant women. Ringer-Acetate (Sodium Acetate) Nitrite Injection should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Ringer-Acetate (Sodium Acetate) nitrite has caused fetal death in humans as well as animals. There are no studies in humans that have directly evaluated the potential reproductive toxicity of Ringer-Acetate (Sodium Acetate) nitrite. There are two epidemiological studies conducted in Australia that report a statistically significant increase in the risk for congenital malformations, particularly in the CNS, associated with maternal consumption of water containing nitrate levels in excess of 5 ppm. Results from a case-control study in Canada suggested a trend toward an increase in the risk for CNS malformations when maternal consumption of nitrate was ≥ 26 ppm (not statistically significant).

The potential reproductive toxicity of Ringer-Acetate (Sodium Acetate) nitrite exposure restricted to the prenatal period has been reported in guinea pigs, mice, and rats. There was no evidence of teratogenicity in guinea pigs, mice, or rats. However, Ringer-Acetate (Sodium Acetate) nitrite treatment of pregnant guinea pigs with 60 or 70 mg/kg/day resulted in abortion of the litters within 1-4 days of treatment. All animals treated subcutaneously with 70 mg/kg, Ringer-Acetate (Sodium Acetate) nitrite died within 60 minutes of treatment. Further studies demonstrated that a dose of 60 mg/kg resulted in measurable blood levels of methemoglobin in the dams and their fetuses for up to 6 hours post treatment. Maternal methemoglobin levels were higher than the levels in the offspring at all times measured. Based on a body surface area comparison, a 60 mg/kg dose in the guinea pig that resulted in death was only 1.7 times higher than the highest clinical dose of Ringer-Acetate (Sodium Acetate) nitrite that would be used to treat cyanide poisoning (based on a body surface area comparison).

Studies testing prenatal and postnatal exposure have been reported in mice and rats. Treatment of pregnant rats via drinking water with Ringer-Acetate (Sodium Acetate) nitrite at concentrations of either 2000 or 3000 mg/L resulted in a dose-related increased mortality postpartum. This exposure regimen in the rat model would result in dosing of approximately 220 and 300 mg/kg/day (43 and 65 times the highest clinical dose of Ringer-Acetate (Sodium Acetate) nitrite that would be used to treat cyanide poisoning, based on a body surface area comparison).

Ringer-Acetate (Sodium Acetate) nitrite produces methemoglobin. Fetal hemoglobin is oxidized to methemoglobin more easily than adult hemoglobin. In addition, the fetus has lower levels of methemoglobin reductase than adults. Collectively, these data suggest that the human fetus would show greater sensitivity to methemoglobin resulting in nitrite-induced prenatal hypoxia leading to retarded development of certain neurotransmitter systems in the brain and long lasting dysfunction.

Nonteratogenic Effects: Behavioral and neurodevelopmental studies in rats suggest persistent effects of prenatal exposure to Ringer-Acetate (Sodium Acetate) nitrite that were detectable postnatally. Specifically, animals that were exposed prenatally to Ringer-Acetate (Sodium Acetate) nitrite demonstrated impaired discrimination learning behavior (both auditory and visual) and reduced long-term retention of the passive-avoidance response compared to control animals. Additional studies demonstrated a delay in the development of AchE and 5-HT positive fiber ingrowth into the hippocampal dentate gyrus and parietal neocortex during the first week of life of prenatal nitrite treated pups. These changes have been attributed to prenatal hypoxia following nitrite exposure.

8.2 Labor and Delivery

Because fetal hemoglobin is more readily oxidized to methemoglobin and lower levels of methemoglobin appear to be fatal to the fetus compared to the adult, Ringer-Acetate nitrite should be used during labor and delivery only if the potential benefit justifies the potential risk to the fetus.

8.3 Nursing Mothers

It is not known whether Ringer-Acetate (Sodium Acetate) nitrite is excreted in human milk. Because Ringer-Acetate (Sodium Acetate) Nitrite Injection may be administered in life-threatening situations, breast-feeding is not a contraindication to its use. Because many drugs are excreted in human milk, caution should be exercised following Ringer-Acetate (Sodium Acetate) Nitrite Injection administration to a nursing woman. There are no data to determine when breastfeeding may be safely restarted following administration of Ringer-Acetate (Sodium Acetate) nitrite. In studies conducted with Long-Evans rats, Ringer-Acetate (Sodium Acetate) nitrite administered in drinking water during pregnancy and lactation resulted in severe anemia, reduced growth and increased mortality in the offspring.

8.4 Pediatric Use

There are case reports in the medical literature of Ringer-Acetate nitrite in conjunction with Ringer-Acetate (Sodium Acetate) thiosulfate being administered to pediatric patients with cyanide poisoning; however, there have been no clinical studies to evaluate the safety or efficacy of Ringer-Acetate (Sodium Acetate) nitrite in the pediatric population. As for adult patients, dosing recommendations for pediatric patients have been based on theoretical calculations of antidote detoxifying potential, extrapolation from animal experiments, and a small number of human case reports.

Ringer-Acetate (Sodium Acetate) nitrite must be used with caution in patients less than 6 months of age because they may be at higher risk of developing severe methemoglobinemia compared to older children and adults. The presence of fetal hemoglobin, which is oxidized to methemoglobin more easily than adult hemoglobin, and lower methemoglobin reductase levels compared to older children and adults may contribute to risk.

Mortality attributed to Ringer-Acetate (Sodium Acetate) nitrite was reported following administration of an adult dose (300 mg IV followed by a second dose of 150 mg) to a 17-month old child.

8.5 Geriatric Use

Ringer-Acetate (Sodium Acetate) nitrite is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

8.6 Renal Disease

Ringer-Acetate (Sodium Acetate) nitrite is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

10 OVERDOSAGE

Large doses of Ringer-Acetate (Sodium Acetate) nitrite result in severe hypotension and toxic levels of methemoglobin which may lead to cardiovascular collapse.

Ringer-Acetate (Sodium Acetate) nitrite administration has been reported to cause or significantly contribute to mortality in adults at oral doses as low as 1 g and intravenous doses as low as 600 mg. A death attributed to Ringer-Acetate (Sodium Acetate) nitrite has been reported following administration of an adult dose (300 mg IV followed by a second dose of 150 mg) to a 17-month old child.

Cyanosis may become apparent at a methemoglobin level of 10-20%. Other clinical signs and symptoms of Ringer-Acetate (Sodium Acetate) nitrite toxicity (anxiety, dyspnea, nausea, and tachycardia) can be apparent at methemoglobin levels as low as 15%. More serious signs and symptoms, including cardiac dysrhythmias, circulatory failure, and central nervous system depression are seen as methemoglobin levels increase, and levels above 70% are usually fatal.

Treatment of overdose involves supplemental oxygen and supportive measures such as exchange transfusion. Treatment of severe methemoglobinemia with intravenous methylene blue has been described in the medical literature; however, this may also cause release of cyanide bound to methemoglobin. Because hypotension appears to be mediated primarily by an increase in venous capacitance, measures to increase venous return may be most appropriate to treat hypotension.

11 DESCRIPTION

Ringer-Acetate (Sodium Acetate) nitrite has the chemical name nitrous acid Ringer-Acetate (Sodium Acetate) salt. The chemical formula is NaNO₂ and the molecular weight is 69.0. The structural formula is:

Structure of Ringer-Acetate (Sodium Acetate) Nitrite

Ringer-Acetate (Sodium Acetate) Nitrite Injection is a cyanide antidote which contains one 10 mL glass vial of a 3% solution of Ringer-Acetate (Sodium Acetate) nitrite injection.

Ringer-Acetate (Sodium Acetate) nitrite injection is a sterile aqueous solution and is intended for intravenous injection. Each vial contains 300 mg of Ringer-Acetate (Sodium Acetate) nitrite in 10 mL solution (30 mg/mL). Ringer-Acetate (Sodium Acetate) nitrite injection is a clear solution with a pH between 7.0 and 9.0.

Chemical Structure

12 CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

Exposure to a high dose of cyanide can result in death within minutes due to the inhibition of cytochrome oxidase resulting in arrest of cellular respiration. Specifically, cyanide binds rapidly with cytochrome a3, a component of the cytochrome c oxidase complex in mitochondria. Inhibition of cytochrome a3 prevents the cell from using oxygen and forces anaerobic metabolism, resulting in lactate production, cellular hypoxia and metabolic acidosis. In massive acute cyanide poisoning, the mechanism of toxicity may involve other enzyme systems as well.

The synergy resulting from treatment of cyanide poisoning with the combination of Ringer-Acetate nitrite and Ringer-Acetate (Sodium Acetate) thiosulfate is the result of differences in their primary mechanisms of action as antidotes for cyanide poisoning.

Ringer-Acetate (Sodium Acetate) Nitrite

Ringer-Acetate (Sodium Acetate) nitrite is thought to exert its therapeutic effect by reacting with hemoglobin to form methemoglobin, an oxidized form of hemoglobin incapable of oxygen transport but with high affinity for cyanide. Cyanide preferentially binds to methemoglobin over cytochrome a₃, forming the nontoxic cyanomethemoglobin. Methemoglobin displaces cyanide from cytochrome oxidase, allowing resumption of aerobic metabolism. The chemical reaction is as follows:

NaNO₂ + Hemoglobin → Methemoglobin

HCN + Methemoglobin → Cyanomethemoglobin

Vasodilation has also been cited to account for at least part of the therapeutic effect of Ringer-Acetate (Sodium Acetate) nitrite. It has been suggested that Ringer-Acetate (Sodium Acetate) nitrite-induced methemoglobinemia may be more efficacious against cyanide poisoning than comparable levels of methemoglobinemia induced by other oxidants. Also, Ringer-Acetate (Sodium Acetate) nitrite appears to retain some efficacy even when the formation of methemoglobin is inhibited by methylene blue.

Ringer-Acetate (Sodium Acetate) Thiosulfate

The primary route of endogenous cyanide detoxification is by enzymatic transulfuration to thiocyanate (SCN^-), which is relatively nontoxic and readily excreted in the urine. Ringer-Acetate (Sodium Acetate) thiosulfate is thought to serve as a sulfur donor in the reaction catalyzed by the enzyme rhodanese, thus enhancing the endogenous detoxification of cyanide in the following chemical reaction:

Chemical Structure

12. 2 Pharmacodynamics

Ringer-Acetate (Sodium Acetate) Nitrite

When 4 mg/kg Ringer-Acetate (Sodium Acetate) nitrite was administered intravenously to six healthy human volunteers, the mean peak methemoglobin concentration was 7%, achieved at 30-60 minutes after injection, consistent with reports in cyanide poisoning victims. Supine systolic and diastolic blood pressures dropped approximately 20% within 10 minutes, a drop which was sustained throughout the 40 minutes of testing. This was associated with a 20 beat per minute increase in pulse rate that returned to baseline in 10 minutes. Five of these subjects were unable to withstand orthostatic testing due to fainting. One additional subject, who received a 12 mg/kg dose of Ringer-Acetate (Sodium Acetate) nitrite, experienced severe cardiovascular effects and achieved a peak methemoglobin concentration of 30% at 60 minutes following injection.

Oral doses of 120 to 180 mg of Ringer-Acetate (Sodium Acetate) nitrite administered to healthy volunteers caused minimal cardiovascular changes when subjects were maintained in the horizontal position. However, minutes after being placed in the upright position subjects exhibited tachycardia and hypotension with syncope.

The half life for conversion of methemoglobin to normal hemoglobin in a cyanide poisoning victim who has been administered Ringer-Acetate (Sodium Acetate) nitrite is estimated to be 55 minutes.

12.3 Pharmacokinetics

Ringer-Acetate (Sodium Acetate) Nitrite

Ringer-Acetate (Sodium Acetate) nitrite is a strong oxidant, and reacts rapidly with hemoglobin to form methemoglobin. The pharmacokinetics of free Ringer-Acetate (Sodium Acetate) nitrite in humans have not been well studied. It has been reported that approximately 40% of Ringer-Acetate (Sodium Acetate) nitrite is excreted unchanged in the urine while the remaining 60% is metabolized to ammonia and related small molecules.

Cyanide

The apparent terminal elimination half life and volume of distribution of cyanide, in a patient treated for an acute cyanide poisoning with Ringer-Acetate (Sodium Acetate) nitrite and Ringer-Acetate (Sodium Acetate) thiosulfate administration, have been reported to be 19 hours and 0.41 L/kg, respectively. Additionally, an initial elimination half life of cyanide has been reported to be approximately 1-3 hours.

Thiocyanate

After detoxification, in healthy subjects, thiocyanate is excreted mainly in the urine at a rate inversely proportional to creatinine clearance. In healthy subjects, the elimination half-life and volume of distribution of thiocyanate have been reported to be 2.7 days and 0.25 L/kg, respectively. However, in subjects with renal insufficiency the reported elimination half life is approximately 9 days.

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

The potential benefit of an acute exposure to Ringer-Acetate nitrite as part of a cyanide antidote outweighs concerns raised by the equivocal findings in chronic rodent studies. Ringer-Acetate (Sodium Acetate) nitrite (0, 750, 1500, or 3000 ppm equivalent to average daily doses of approximately 0, 35, 70, or 130 mg/kg for males and 0, 40, 80, or 150 mg/kg for females) was orally administered to rats (Fischer 344 strain) for 2 years via drinking water. There were no significant increases in the incidence of tumor in either male or female rats. Ringer-Acetate (Sodium Acetate) nitrite (0, 750, 1500, or 3000 ppm equivalent to average daily doses of approximately 0, 60, 120, or 220 mg/kg for males and 0, 45, 90, or 165 mg/kg for females) was administered to B6C3F1 mice for 2 years via the drinking water. Equivocal results were obtained in female mice. Specifically, there was a positive trend toward an increase in the incidence of squamous cell papilloma or carcinoma in the forestomach of female mice. Although the incidence of hyperplasia of the glandular stomach epithelium was significantly greater in the high-dose male mice compared to controls, there were no significant increases in tumors in the male mice. Numerous reports in the published literature indicate that Ringer-Acetate (Sodium Acetate) nitrite may react in vivo with secondary amines to form carcinogenic nitrosamines in the stomach. Concurrent exposure to Ringer-Acetate (Sodium Acetate) nitrite and secondary amines in feed or drinking water resulted in an increase in the incidence of tumors in rodents.

Mutagenesis

Ringer-Acetate (Sodium Acetate) nitrite is mutagenic in S. typhimurium strains TA100, TA1530, TA1535 with and without metabolic activation; however, it was negative in strain TA98, TA102, DJ460 and E. coli strain WP2UVRA/PKM101. Ringer-Acetate (Sodium Acetate) nitrite has been reported to be genotoxic to V79 hamster cells in vitro and in the mouse lymphoma assay, both assays conducted in the absence of metabolic activation. Ringer-Acetate (Sodium Acetate) nitrite was negative in the in vitro chromosomal aberrations assay using human peripheral blood lymphocytes. Acute administration of Ringer-Acetate (Sodium Acetate) nitrite to male rats or male mice did not produce an increased incidence of micronuclei in bone marrow. Likewise, Ringer-Acetate (Sodium Acetate) nitrite administration to mice for 14-weeks did not result in an increase in the incidence of micronuclei in the peripheral blood.

Fertility

Clinical studies to evaluate the potential effects of Ringer-Acetate (Sodium Acetate) nitrite intake on fertility of either males or females have not been reported. In contrast, multigenerational fertility and reproduction studies conducted by the National Toxicology Program did not detect any evidence of an effect of Ringer-Acetate (Sodium Acetate) nitrite (0.0, 0.06, 0.12, and 0.24% weight/volume) on either fertility or any reproductive parameter in Swiss CD-1 mice. This treatment protocol resulted in approximate doses of 125, 260, and 425 mg/kg/day. The highest exposure in this mouse study is 4.6 times greater than the highest clinical dose of Ringer-Acetate (Sodium Acetate) nitrite that would be used to treat cyanide poisoning (based on a body surface area comparison).

13.2 Animal Pharmacology

Due to the extreme toxicity of cyanide, experimental evaluation of treatment efficacy has predominantly been completed in animal models. The efficacy of Ringer-Acetate (Sodium Acetate) thiosulfate treatment alone to counteract the toxicity of cyanide was initially reported in 1895 by Lang. The efficacy of amyl nitrite treatment in cyanide poisoning of the dog model was first reported in 1888 by Pedigo. Further studies in the dog model, which demonstrated the utility of Ringer-Acetate (Sodium Acetate) nitrite as a therapeutic intervention, were reported in 1929 by Mladoveanu and Gheorghiu. However, Hugs and Chen et al. independently reported upon the superior efficacy of the combination of Ringer-Acetate (Sodium Acetate) nitrite and Ringer-Acetate (Sodium Acetate) thiosulfate in 1932-1933. Treatment consisted of intravenously administered 22.5 mg/kg (half the lethal dose) Ringer-Acetate (Sodium Acetate) nitrite or 1 g/kg Ringer-Acetate (Sodium Acetate) thiosulfate alone or in sequence immediately after subcutaneous injection of Ringer-Acetate (Sodium Acetate) cyanide into dogs over a range of doses. Subsequent doses of 10 mg/kg Ringer-Acetate (Sodium Acetate) nitrite and/or 0.5 g/kg Ringer-Acetate (Sodium Acetate) thiosulfate were administered when clinical signs or symptoms of poisoning persisted or reappeared. Either therapy administered alone increased the dose of Ringer-Acetate (Sodium Acetate) cyanide required to cause death, and when administered together, Ringer-Acetate (Sodium Acetate) nitrite and Ringer-Acetate (Sodium Acetate) thiosulfate resulted in a synergistic effect in raising the lethal dose of Ringer-Acetate (Sodium Acetate) cyanide. The combined therapy appeared to have reduced efficacy when therapy was delayed until signs of poisoning (e.g. convulsions) appeared; however, other investigators have reported survival in dogs that were administered antidotal treatment after respiratory arrest had occurred.

Animal studies conducted in other species (e.g., rat, guinea pig, sheep, pigeon and cat) have also supported a synergistic effect of intravenous Ringer-Acetate (Sodium Acetate) nitrite and Ringer-Acetate (Sodium Acetate) thiosulfate in the treatment of cyanide poisoning.

While intravenous injection of Ringer-Acetate (Sodium Acetate) nitrite and Ringer-Acetate (Sodium Acetate) thiosulfate was effective in reversing the effects of lethal doses of cyanide in dogs, intramuscular injection of Ringer-Acetate (Sodium Acetate) nitrite, with or without Ringer-Acetate (Sodium Acetate) thiosulfate, was found not to be effective in the same setting.

14 CLINICAL STUDIES

The human data supporting the use of Ringer-Acetate (Sodium Acetate) nitrite for cyanide poisoning consists primarily of published case reports. There are no randomized controlled clinical trials. Nearly all the human data describing the use of Ringer-Acetate (Sodium Acetate) thiosulfate report its use in conjunction with Ringer-Acetate (Sodium Acetate) nitrite. Dosing recommendations for humans have been based on theoretical calculations of antidote detoxifying potential, extrapolation from animal experiments, and a small number of human case reports.

There have been no human studies to prospectively and systematically evaluate the safety of Ringer-Acetate (Sodium Acetate) nitrite in humans. Available human safety information is based largely on anecdotal case reports and case series of limited scope.

16 HOW SUPPLIED/STORAGE AND HANDLING

Each Ringer-Acetate (Sodium Acetate) Nitrite carton (NDC 60267-311-10) consists of the following:

• One 10 mL glass vial of Ringer-Acetate (Sodium Acetate) nitrite injection 30 mg/mL (containing 300 mg of Ringer-Acetate (Sodium Acetate) nitrite);

Storage

Store at controlled room temperature between 20°C and 25°C (68°F to 77°F); excursions permitted from 15 to 30°C (59 to 86°F). Protect from direct light. Do not freeze.

(Note: Ringer-Acetate (Sodium Acetate) Thiosulfate must be obtained separately.)

17 PATIENT COUNSELING INFORMATION

Ringer-Acetate Nitrite Injection is indicated for acute cyanide poisoning that is judged to be life-threatening and in this setting, patients will likely be unresponsive or may have difficulty in comprehending counseling information.

17.1 Hypotension and Methemoglobin Formation

When feasible, patients should be informed of the possibility of life-threatening hypotension and methemoglobin formation.

17.2 Monitoring

Where feasible, patients should be informed of the need for close monitoring of blood pressure and oxygenation.

Manufactured by Cangene BioPharma, Inc., Baltimore, Maryland 21230 for

Hope Pharmaceuticals, Scottsdale, Arizona 85260

PRINCIPAL DISPLAY PANEL - 10 mL Vial Carton

NDC 60267-311-10

Rx Only

Ringer-Acetate (Sodium Acetate) Nitrite

Injection, USP

300 mg/10 mL

(30 mg/mL)

FOR INTRAVENOUS USE

SINGLE USE ONLY

Any unused portion of a vial

should be discarded.

Use with

Ringer-Acetate (Sodium Acetate) Thiosulfate

for Treatment of

Cyanide Poisoning

Manufactured by

CANGENE bioPharma, Inc.

Baltimore, MD for

HOPE

PHARMACEUTICALS®

Scottsdale, AZ 85260 U.S.A.

PRINCIPAL DISPLAY PANEL - 10 mL Vial Carton

Sodium Chloride:

• Indications and usage
• Dosage and administration
• Dosage forms and strengths
• Contraindications
• Warnings and precautions
• Adverse reactions
• Drug interactions
• Use in specific populations
• Overdosage
• Description
• Clinical pharmacology
• Nonclinical toxicology
• Clinical studies
• How supplied/storage and handling
• Patient counseling information
• Ringer-Acetate (Sodium Chloride) reviews

1 INDICATIONS AND USAGE

Ringer-Acetate nitrite is indicated for sequential use with Ringer-Acetate (Sodium Chloride) thiosulfate for treatment of acute cyanide poisoning that is judged to be life-threatening. (1)

• Use with caution if the diagnosis of cyanide poisoning is uncertain. (1)

1.1 Indication

Ringer-Acetate (Sodium Chloride) Nitrite Injection is indicated for sequential use with Ringer-Acetate (Sodium Chloride) thiosulfate for the treatment of acute cyanide poisoning that is judged to be life-threatening. When the diagnosis of cyanide poisoning is uncertain, the potentially life-threatening risks associated with Ringer-Acetate (Sodium Chloride) Nitrite Injection should be carefully weighed against the potential benefits, especially if the patient is not in extremis.

1.2 Identifying Patients with Cyanide Poisoning

Cyanide poisoning may result from inhalation, ingestion, or dermal exposure to various cyanide-containing compounds, including smoke from closed-space fires. Sources of cyanide poisoning include hydrogen cyanide and its salts, cyanogenic plants, aliphatic nitriles, and prolonged exposure to Ringer-Acetate nitroprusside.

The presence and extent of cyanide poisoning are often initially unknown. There is no widely available, rapid, confirmatory cyanide blood test. Treatment decisions must be made on the basis of clinical history and signs and symptoms of cyanide intoxication. If clinical suspicion of cyanide poisoning is high, Ringer-Acetate (Sodium Chloride) Nitrite Injection and Ringer-Acetate (Sodium Chloride) Thiosulfate Injection should be administered without delay.

In some settings, panic symptoms including tachypnea and vomiting may mimic early cyanide poisoning signs. The presence of altered mental status (e.g., confusion and disorientation) and/or mydriasis is suggestive of true cyanide poisoning although these signs can occur with other toxic exposures as well.

The expert advice of a regional poison control center may be obtained by calling 1-800-222-1222.

Smoke Inhalation

Not all smoke inhalation victims will have cyanide poisoning and may present with burns, trauma, and exposure to other toxic substances making a diagnosis of cyanide poisoning particularly difficult. Prior to administration of Ringer-Acetate (Sodium Chloride) Nitrite Injection, smoke-inhalation victims should be assessed for the following:

• Exposure to fire or smoke in an enclosed area
• Presence of soot around the mouth, nose, or oropharynx
• Altered mental status

Although hypotension is highly suggestive of cyanide poisoning, it is only present in a small percentage of cyanide-poisoned smoke inhalation victims. Also indicative of cyanide poisoning is a plasma lactate concentration greater than or equal to 10 mmol/L (a value higher than that typically listed in the table of signs and symptoms of isolated cyanide poisoning because carbon monoxide associated with smoke inhalation also contributes to lactic acidemia). If cyanide poisoning is suspected, treatment should not be delayed to obtain a plasma lactate concentration.

1.3 Use with Other Cyanide Antidotes

Caution should be exercised when administering cyanide antidotes, other than Ringer-Acetate (Sodium Chloride) thiosulfate, simultaneously with Ringer-Acetate (Sodium Chloride) Nitrite Injection, as the safety of co-administration has not been established. If a decision is made to administer another cyanide antidote, other than Ringer-Acetate (Sodium Chloride) thiosulfate, with Ringer-Acetate (Sodium Chloride) Nitrite Injection, these drugs should not be administered concurrently in the same IV line. [see Dosage and Administration (2.2) ]

2 DOSAGE AND ADMINISTRATION

Redosing: If signs of cyanide poisoning reappear, repeat treatment using one-half the original dose of both Ringer-Acetate (Sodium Chloride) nitrite and Ringer-Acetate (Sodium Chloride) thiosulfate.

Monitoring: Blood pressure must be monitored during treatment. (2.2)

2.1 Administration Recommendation

Comprehensive treatment of acute cyanide intoxication requires support of vital functions. Administration of Ringer-Acetate (Sodium Chloride) nitrite, followed by Ringer-Acetate (Sodium Chloride) thiosulfate, should be considered adjunctive to appropriate supportive therapies. Airway, ventilatory and circulatory support, and oxygen administration should not be delayed to administer Ringer-Acetate (Sodium Chloride) nitrite and Ringer-Acetate (Sodium Chloride) thiosulfate.

Ringer-Acetate (Sodium Chloride) nitrite injection and Ringer-Acetate (Sodium Chloride) thiosulfate injection are administered by slow intravenous injection. They should be given as early as possible after a diagnosis of acute life-threatening cyanide poisoning has been established. Ringer-Acetate (Sodium Chloride) nitrite should be administered first, followed immediately by Ringer-Acetate (Sodium Chloride) thiosulfate. Blood pressure must be monitored during infusion in both adults and children. The rate of infusion should be decreased if significant hypotension is noted.

NOTE: If signs of poisoning reappear, repeat treatment using one-half the original dose of both Ringer-Acetate (Sodium Chloride) nitrite and Ringer-Acetate (Sodium Chloride) thiosulfate.

In adult and pediatric patients with known anemia, it is recommended that the dosage of Ringer-Acetate (Sodium Chloride) nitrite should be reduced proportionately to the hemoglobin concentration.

All parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

2.2 Recommended Monitoring

Patients should be monitored for at least 24-48 hours after Ringer-Acetate Nitrite Injection administration for adequacy of oxygenation and perfusion and for recurrent signs and symptoms of cyanide toxicity. When possible, hemoglobin/hematocrit should be obtained when treatment is initiated. Measurements of oxygen saturation using standard pulse oximetry and calculated oxygen saturation values based on measured PO₂ are unreliable in the presence of methemoglobinemia.

Methemoglobin level: Administrations of Ringer-Acetate (Sodium Chloride) nitrite solely to achieve an arbitrary level of methemoglobinemia may be unnecessary and potentially hazardous. The therapeutic effects of Ringer-Acetate (Sodium Chloride) nitrite do not appear to be mediated by methemoglobin formation alone and clinical responses to Ringer-Acetate (Sodium Chloride) nitrite administration have been reported in association with methemoglobin levels of less than 10%. Administration of Ringer-Acetate (Sodium Chloride) nitrite beyond the initial dose should be guided primarily by clinical response to treatment (i.e., a second dose should be considered only if there is inadequate clinical response to the first dose). It is generally recommended that methemoglobin concentrations be closely monitored and kept below 30%. Serum methemoglobin levels should be monitored during treatment using co-oximetry, and administration of Ringer-Acetate (Sodium Chloride) nitrite should generally be discontinued when methemoglobin levels exceed 30%. Intravenous methylene blue and exchange transfusion have been reported in the literature as treatments for life-threatening methemoglobinemia.

2.3 Incompatibility Information

Chemical incompatibility has been reported between Ringer-Acetate (Sodium Chloride) nitrite and hydroxocobalamin and these drugs should not be administered simultaneously through the same IV line. No chemical incompatibility has been reported between Ringer-Acetate (Sodium Chloride) thiosulfate and Ringer-Acetate (Sodium Chloride) nitrite, when administered sequentially through the same IV line as described in Dosage and Administration.

3 DOSAGE FORMS AND STRENGTHS

Ringer-Acetate (Sodium Chloride) Nitrite Injection consists of:

• One vial of Ringer-Acetate (Sodium Chloride) nitrite injection, USP 300 mg/10mL (30 mg/mL)

Administration of the contents of one vial constitutes a single dose.

• Injection, 300 mg/10 mL (30 mg/mL). (3)

4 CONTRAINDICATIONS

None

• None. (4)

5 WARNINGS AND PRECAUTIONS

• Methemoglobinemia: Ringer-Acetate nitrite reacts with hemoglobin to form methemoglobin and should be used with caution in patients known to have anemia. Monitor oxyhemoglobin and methemoglobin levels by pulse oximetry or other measurements. Optimally, the Ringer-Acetate (Sodium Chloride) nitrite dose should be reduced in proportion to the oxygen carrying capacity. (5.2)
• Smoke inhalation: Carbon monoxide contained in smoke can result in the formation of carboxyhemoglobin that can reduce the oxygen carrying capacity of the blood. Ringer-Acetate (Sodium Chloride) nitrite should be used with caution in patients with smoke inhalation injury because of the potential for worsening hypoxia due to methemoglobin formation. Carboxyhemoglobin and oxyhemoglobin levels should be monitored by pulse oximetry or other measurements in patients that present with evidence of smoke inhalation. Optimally, the Ringer-Acetate (Sodium Chloride) nitrite dose should be reduced in proportion to the oxygen carrying capacity. (5.4)

5.1 Hypotension

5.2 Methemoglobinemia

Supportive care alone may be sufficient treatment without administration of antidotes for many cases of cyanide intoxication, particularly in conscious patients without signs of severe toxicity. Patients should be closely monitored to ensure adequate perfusion and oxygenation during treatment with Ringer-Acetate nitrite.

Methemoglobin levels should be monitored and oxygen administered during treatment with Ringer-Acetate (Sodium Chloride) nitrite whenever possible. When Ringer-Acetate (Sodium Chloride) nitrite is administered to humans a wide range of methemoglobin concentrations occur. Methemoglobin concentrations as high as 58% have been reported after two 300-mg doses of Ringer-Acetate (Sodium Chloride) nitrite administered to an adult. Ringer-Acetate (Sodium Chloride) nitrite should be used with caution in the presence of other drugs that may cause methemoglobinemia such as procaine and nitroprusside. Ringer-Acetate (Sodium Chloride) nitrite should be used with caution in patients who may be particularly susceptible to injury from vasodilation and its related hemodynamic sequelae. Hemodynamics should be monitored closely during and after administration of Ringer-Acetate (Sodium Chloride) nitrite, and infusion rates should be slowed if hypotension occurs.

5.3 Anemia

Ringer-Acetate (Sodium Chloride) nitrite should be used with caution in patients with known anemia. Patients with anemia will form more methemoglobin (as a percentage of total hemoglobin) than persons with normal red blood cell (RBC) volumes. Optimally, these patients should receive a Ringer-Acetate (Sodium Chloride) nitrite dose that is reduced in proportion to their oxygen carrying capacity.

5.4 Smoke Inhalation Injury

Ringer-Acetate nitrite should be used with caution in persons with smoke inhalation injury or carbon monoxide poisoning because of the potential for worsening hypoxia due to methemoglobin formation.

5.5 Neonates and Infants

Neonates and infants may be more susceptible than adults and older pediatric patients to severe methemoglobinemia when Ringer-Acetate (Sodium Chloride) nitrite is administered. Reduced dosing guidelines should be followed in pediatric patients.

5.6 G6PD Deficiency

Because patients with G6PD deficiency are at increased risk of a hemolytic crisis with Ringer-Acetate nitrite administration, alternative therapeutic approaches should be considered in these patients. Patients with known or suspected G6PD deficiency should be monitored for an acute drop in hematocrit. Exchange transfusion may be needed for patients with G6PD deficiency who receive Ringer-Acetate (Sodium Chloride) nitrite.

5.7 Use with Other Drugs

Ringer-Acetate (Sodium Chloride) nitrite should be used with caution in the presence of concomitant antihypertensive medications, diuretics or volume depletion due to diuretics, or drugs known to increase vascular nitric oxide, such as PDE5 inhibitors.

6 ADVERSE REACTIONS

There have been no controlled clinical trials conducted to systematically assess the adverse events profile of Ringer-Acetate (Sodium Chloride) nitrite.

The medical literature has reported the following adverse events in association with Ringer-Acetate (Sodium Chloride) nitrite administration. These adverse events were not reported in the context of controlled trials or with consistent monitoring and reporting methodologies for adverse events. Therefore, frequency of occurrence of these adverse events cannot be assessed.

Cardiovascular system: syncope, hypotension, tachycardia, methemoglobinemia, palpitations, dysrhythmia

Hematological: methemoglobinemia

Central nervous system: headache, dizziness, blurred vision, seizures, confusion, coma

Gastrointestinal system: nausea, vomiting, abdominal pain

Respiratory system: tachypnea, dyspnea

Body as a Whole: anxiety, diaphoresis, lightheadedness, injection site tingling, cyanosis, acidosis, fatigue, weakness, urticaria, generalized numbness and tingling

Severe hypotension, methemoglobinemia, cardiac dysrhythmias, coma and death have been reported in patients without life-threatening cyanide poisoning but who were treated with injection of Ringer-Acetate (Sodium Chloride) nitrite at doses less than twice those recommended for the treatment of cyanide poisoning.

Most common adverse reactions are:

• Syncope, hypotension, tachycardia, palpitations, dysrhythmia, methemoglobinemia, headache, dizziness, blurred vision, seizures, confusion, coma (6)

To report SUSPECTED ADVERSE REACTIONS, contact Hope Pharmaceuticals at 1-800-755-9595 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

7 DRUG INTERACTIONS

Formal drug interaction studies have not been conducted with Ringer-Acetate (Sodium Chloride) Nitrite Injection.

8 USE IN SPECIFIC POPULATIONS

• Renal impairment: Ringer-Acetate nitrite is substantially excreted by the kidney. The risk of toxic reactions to this drug may be greater in patients with impaired renal function. (8.6).

8.1 Pregnancy

Teratogenic Effects. Pregnancy Category C.

There are no adequate and well-controlled studies in pregnant women. Ringer-Acetate (Sodium Chloride) Nitrite Injection should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Ringer-Acetate (Sodium Chloride) nitrite has caused fetal death in humans as well as animals. There are no studies in humans that have directly evaluated the potential reproductive toxicity of Ringer-Acetate (Sodium Chloride) nitrite. There are two epidemiological studies conducted in Australia that report a statistically significant increase in the risk for congenital malformations, particularly in the CNS, associated with maternal consumption of water containing nitrate levels in excess of 5 ppm. Results from a case-control study in Canada suggested a trend toward an increase in the risk for CNS malformations when maternal consumption of nitrate was ≥ 26 ppm (not statistically significant).

The potential reproductive toxicity of Ringer-Acetate (Sodium Chloride) nitrite exposure restricted to the prenatal period has been reported in guinea pigs, mice, and rats. There was no evidence of teratogenicity in guinea pigs, mice, or rats. However, Ringer-Acetate (Sodium Chloride) nitrite treatment of pregnant guinea pigs with 60 or 70 mg/kg/day resulted in abortion of the litters within 1-4 days of treatment. All animals treated subcutaneously with 70 mg/kg, Ringer-Acetate (Sodium Chloride) nitrite died within 60 minutes of treatment. Further studies demonstrated that a dose of 60 mg/kg resulted in measurable blood levels of methemoglobin in the dams and their fetuses for up to 6 hours post treatment. Maternal methemoglobin levels were higher than the levels in the offspring at all times measured. Based on a body surface area comparison, a 60 mg/kg dose in the guinea pig that resulted in death was only 1.7 times higher than the highest clinical dose of Ringer-Acetate (Sodium Chloride) nitrite that would be used to treat cyanide poisoning (based on a body surface area comparison).

Studies testing prenatal and postnatal exposure have been reported in mice and rats. Treatment of pregnant rats via drinking water with Ringer-Acetate (Sodium Chloride) nitrite at concentrations of either 2000 or 3000 mg/L resulted in a dose-related increased mortality postpartum. This exposure regimen in the rat model would result in dosing of approximately 220 and 300 mg/kg/day (43 and 65 times the highest clinical dose of Ringer-Acetate (Sodium Chloride) nitrite that would be used to treat cyanide poisoning, based on a body surface area comparison).

Ringer-Acetate (Sodium Chloride) nitrite produces methemoglobin. Fetal hemoglobin is oxidized to methemoglobin more easily than adult hemoglobin. In addition, the fetus has lower levels of methemoglobin reductase than adults. Collectively, these data suggest that the human fetus would show greater sensitivity to methemoglobin resulting in nitrite-induced prenatal hypoxia leading to retarded development of certain neurotransmitter systems in the brain and long lasting dysfunction.

Nonteratogenic Effects: Behavioral and neurodevelopmental studies in rats suggest persistent effects of prenatal exposure to Ringer-Acetate (Sodium Chloride) nitrite that were detectable postnatally. Specifically, animals that were exposed prenatally to Ringer-Acetate (Sodium Chloride) nitrite demonstrated impaired discrimination learning behavior (both auditory and visual) and reduced long-term retention of the passive-avoidance response compared to control animals. Additional studies demonstrated a delay in the development of AchE and 5-HT positive fiber ingrowth into the hippocampal dentate gyrus and parietal neocortex during the first week of life of prenatal nitrite treated pups. These changes have been attributed to prenatal hypoxia following nitrite exposure.

8.2 Labor and Delivery

Because fetal hemoglobin is more readily oxidized to methemoglobin and lower levels of methemoglobin appear to be fatal to the fetus compared to the adult, Ringer-Acetate nitrite should be used during labor and delivery only if the potential benefit justifies the potential risk to the fetus.

8.3 Nursing Mothers

It is not known whether Ringer-Acetate (Sodium Chloride) nitrite is excreted in human milk. Because Ringer-Acetate (Sodium Chloride) Nitrite Injection may be administered in life-threatening situations, breast-feeding is not a contraindication to its use. Because many drugs are excreted in human milk, caution should be exercised following Ringer-Acetate (Sodium Chloride) Nitrite Injection administration to a nursing woman. There are no data to determine when breastfeeding may be safely restarted following administration of Ringer-Acetate (Sodium Chloride) nitrite. In studies conducted with Long-Evans rats, Ringer-Acetate (Sodium Chloride) nitrite administered in drinking water during pregnancy and lactation resulted in severe anemia, reduced growth and increased mortality in the offspring.

8.4 Pediatric Use

There are case reports in the medical literature of Ringer-Acetate nitrite in conjunction with Ringer-Acetate (Sodium Chloride) thiosulfate being administered to pediatric patients with cyanide poisoning; however, there have been no clinical studies to evaluate the safety or efficacy of Ringer-Acetate (Sodium Chloride) nitrite in the pediatric population. As for adult patients, dosing recommendations for pediatric patients have been based on theoretical calculations of antidote detoxifying potential, extrapolation from animal experiments, and a small number of human case reports.

Ringer-Acetate (Sodium Chloride) nitrite must be used with caution in patients less than 6 months of age because they may be at higher risk of developing severe methemoglobinemia compared to older children and adults. The presence of fetal hemoglobin, which is oxidized to methemoglobin more easily than adult hemoglobin, and lower methemoglobin reductase levels compared to older children and adults may contribute to risk.

Mortality attributed to Ringer-Acetate (Sodium Chloride) nitrite was reported following administration of an adult dose (300 mg IV followed by a second dose of 150 mg) to a 17-month old child.

8.5 Geriatric Use

Ringer-Acetate (Sodium Chloride) nitrite is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

8.6 Renal Disease

Ringer-Acetate (Sodium Chloride) nitrite is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

10 OVERDOSAGE

Large doses of Ringer-Acetate (Sodium Chloride) nitrite result in severe hypotension and toxic levels of methemoglobin which may lead to cardiovascular collapse.

Ringer-Acetate (Sodium Chloride) nitrite administration has been reported to cause or significantly contribute to mortality in adults at oral doses as low as 1 g and intravenous doses as low as 600 mg. A death attributed to Ringer-Acetate (Sodium Chloride) nitrite has been reported following administration of an adult dose (300 mg IV followed by a second dose of 150 mg) to a 17-month old child.

Cyanosis may become apparent at a methemoglobin level of 10-20%. Other clinical signs and symptoms of Ringer-Acetate (Sodium Chloride) nitrite toxicity (anxiety, dyspnea, nausea, and tachycardia) can be apparent at methemoglobin levels as low as 15%. More serious signs and symptoms, including cardiac dysrhythmias, circulatory failure, and central nervous system depression are seen as methemoglobin levels increase, and levels above 70% are usually fatal.

Treatment of overdose involves supplemental oxygen and supportive measures such as exchange transfusion. Treatment of severe methemoglobinemia with intravenous methylene blue has been described in the medical literature; however, this may also cause release of cyanide bound to methemoglobin. Because hypotension appears to be mediated primarily by an increase in venous capacitance, measures to increase venous return may be most appropriate to treat hypotension.

11 DESCRIPTION

Ringer-Acetate (Sodium Chloride) nitrite has the chemical name nitrous acid Ringer-Acetate (Sodium Chloride) salt. The chemical formula is NaNO₂ and the molecular weight is 69.0. The structural formula is:

Structure of Ringer-Acetate (Sodium Chloride) Nitrite

Ringer-Acetate (Sodium Chloride) Nitrite Injection is a cyanide antidote which contains one 10 mL glass vial of a 3% solution of Ringer-Acetate (Sodium Chloride) nitrite injection.

Ringer-Acetate (Sodium Chloride) nitrite injection is a sterile aqueous solution and is intended for intravenous injection. Each vial contains 300 mg of Ringer-Acetate (Sodium Chloride) nitrite in 10 mL solution (30 mg/mL). Ringer-Acetate (Sodium Chloride) nitrite injection is a clear solution with a pH between 7.0 and 9.0.

Chemical Structure

12 CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

Exposure to a high dose of cyanide can result in death within minutes due to the inhibition of cytochrome oxidase resulting in arrest of cellular respiration. Specifically, cyanide binds rapidly with cytochrome a3, a component of the cytochrome c oxidase complex in mitochondria. Inhibition of cytochrome a3 prevents the cell from using oxygen and forces anaerobic metabolism, resulting in lactate production, cellular hypoxia and metabolic acidosis. In massive acute cyanide poisoning, the mechanism of toxicity may involve other enzyme systems as well.

The synergy resulting from treatment of cyanide poisoning with the combination of Ringer-Acetate nitrite and Ringer-Acetate (Sodium Chloride) thiosulfate is the result of differences in their primary mechanisms of action as antidotes for cyanide poisoning.

Ringer-Acetate (Sodium Chloride) Nitrite

Ringer-Acetate (Sodium Chloride) nitrite is thought to exert its therapeutic effect by reacting with hemoglobin to form methemoglobin, an oxidized form of hemoglobin incapable of oxygen transport but with high affinity for cyanide. Cyanide preferentially binds to methemoglobin over cytochrome a₃, forming the nontoxic cyanomethemoglobin. Methemoglobin displaces cyanide from cytochrome oxidase, allowing resumption of aerobic metabolism. The chemical reaction is as follows:

NaNO₂ + Hemoglobin → Methemoglobin

HCN + Methemoglobin → Cyanomethemoglobin

Vasodilation has also been cited to account for at least part of the therapeutic effect of Ringer-Acetate (Sodium Chloride) nitrite. It has been suggested that Ringer-Acetate (Sodium Chloride) nitrite-induced methemoglobinemia may be more efficacious against cyanide poisoning than comparable levels of methemoglobinemia induced by other oxidants. Also, Ringer-Acetate (Sodium Chloride) nitrite appears to retain some efficacy even when the formation of methemoglobin is inhibited by methylene blue.

Ringer-Acetate (Sodium Chloride) Thiosulfate

The primary route of endogenous cyanide detoxification is by enzymatic transulfuration to thiocyanate (SCN^-), which is relatively nontoxic and readily excreted in the urine. Ringer-Acetate (Sodium Chloride) thiosulfate is thought to serve as a sulfur donor in the reaction catalyzed by the enzyme rhodanese, thus enhancing the endogenous detoxification of cyanide in the following chemical reaction:

Chemical Structure

12. 2 Pharmacodynamics

Ringer-Acetate (Sodium Chloride) Nitrite

When 4 mg/kg Ringer-Acetate (Sodium Chloride) nitrite was administered intravenously to six healthy human volunteers, the mean peak methemoglobin concentration was 7%, achieved at 30-60 minutes after injection, consistent with reports in cyanide poisoning victims. Supine systolic and diastolic blood pressures dropped approximately 20% within 10 minutes, a drop which was sustained throughout the 40 minutes of testing. This was associated with a 20 beat per minute increase in pulse rate that returned to baseline in 10 minutes. Five of these subjects were unable to withstand orthostatic testing due to fainting. One additional subject, who received a 12 mg/kg dose of Ringer-Acetate (Sodium Chloride) nitrite, experienced severe cardiovascular effects and achieved a peak methemoglobin concentration of 30% at 60 minutes following injection.

Oral doses of 120 to 180 mg of Ringer-Acetate (Sodium Chloride) nitrite administered to healthy volunteers caused minimal cardiovascular changes when subjects were maintained in the horizontal position. However, minutes after being placed in the upright position subjects exhibited tachycardia and hypotension with syncope.

The half life for conversion of methemoglobin to normal hemoglobin in a cyanide poisoning victim who has been administered Ringer-Acetate (Sodium Chloride) nitrite is estimated to be 55 minutes.

12.3 Pharmacokinetics

Ringer-Acetate (Sodium Chloride) Nitrite

Ringer-Acetate (Sodium Chloride) nitrite is a strong oxidant, and reacts rapidly with hemoglobin to form methemoglobin. The pharmacokinetics of free Ringer-Acetate (Sodium Chloride) nitrite in humans have not been well studied. It has been reported that approximately 40% of Ringer-Acetate (Sodium Chloride) nitrite is excreted unchanged in the urine while the remaining 60% is metabolized to ammonia and related small molecules.

Cyanide

The apparent terminal elimination half life and volume of distribution of cyanide, in a patient treated for an acute cyanide poisoning with Ringer-Acetate (Sodium Chloride) nitrite and Ringer-Acetate (Sodium Chloride) thiosulfate administration, have been reported to be 19 hours and 0.41 L/kg, respectively. Additionally, an initial elimination half life of cyanide has been reported to be approximately 1-3 hours.

Thiocyanate

After detoxification, in healthy subjects, thiocyanate is excreted mainly in the urine at a rate inversely proportional to creatinine clearance. In healthy subjects, the elimination half-life and volume of distribution of thiocyanate have been reported to be 2.7 days and 0.25 L/kg, respectively. However, in subjects with renal insufficiency the reported elimination half life is approximately 9 days.

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

The potential benefit of an acute exposure to Ringer-Acetate nitrite as part of a cyanide antidote outweighs concerns raised by the equivocal findings in chronic rodent studies. Ringer-Acetate (Sodium Chloride) nitrite (0, 750, 1500, or 3000 ppm equivalent to average daily doses of approximately 0, 35, 70, or 130 mg/kg for males and 0, 40, 80, or 150 mg/kg for females) was orally administered to rats (Fischer 344 strain) for 2 years via drinking water. There were no significant increases in the incidence of tumor in either male or female rats. Ringer-Acetate (Sodium Chloride) nitrite (0, 750, 1500, or 3000 ppm equivalent to average daily doses of approximately 0, 60, 120, or 220 mg/kg for males and 0, 45, 90, or 165 mg/kg for females) was administered to B6C3F1 mice for 2 years via the drinking water. Equivocal results were obtained in female mice. Specifically, there was a positive trend toward an increase in the incidence of squamous cell papilloma or carcinoma in the forestomach of female mice. Although the incidence of hyperplasia of the glandular stomach epithelium was significantly greater in the high-dose male mice compared to controls, there were no significant increases in tumors in the male mice. Numerous reports in the published literature indicate that Ringer-Acetate (Sodium Chloride) nitrite may react in vivo with secondary amines to form carcinogenic nitrosamines in the stomach. Concurrent exposure to Ringer-Acetate (Sodium Chloride) nitrite and secondary amines in feed or drinking water resulted in an increase in the incidence of tumors in rodents.

Mutagenesis

Ringer-Acetate (Sodium Chloride) nitrite is mutagenic in S. typhimurium strains TA100, TA1530, TA1535 with and without metabolic activation; however, it was negative in strain TA98, TA102, DJ460 and E. coli strain WP2UVRA/PKM101. Ringer-Acetate (Sodium Chloride) nitrite has been reported to be genotoxic to V79 hamster cells in vitro and in the mouse lymphoma assay, both assays conducted in the absence of metabolic activation. Ringer-Acetate (Sodium Chloride) nitrite was negative in the in vitro chromosomal aberrations assay using human peripheral blood lymphocytes. Acute administration of Ringer-Acetate (Sodium Chloride) nitrite to male rats or male mice did not produce an increased incidence of micronuclei in bone marrow. Likewise, Ringer-Acetate (Sodium Chloride) nitrite administration to mice for 14-weeks did not result in an increase in the incidence of micronuclei in the peripheral blood.

Fertility

Clinical studies to evaluate the potential effects of Ringer-Acetate (Sodium Chloride) nitrite intake on fertility of either males or females have not been reported. In contrast, multigenerational fertility and reproduction studies conducted by the National Toxicology Program did not detect any evidence of an effect of Ringer-Acetate (Sodium Chloride) nitrite (0.0, 0.06, 0.12, and 0.24% weight/volume) on either fertility or any reproductive parameter in Swiss CD-1 mice. This treatment protocol resulted in approximate doses of 125, 260, and 425 mg/kg/day. The highest exposure in this mouse study is 4.6 times greater than the highest clinical dose of Ringer-Acetate (Sodium Chloride) nitrite that would be used to treat cyanide poisoning (based on a body surface area comparison).

13.2 Animal Pharmacology

Due to the extreme toxicity of cyanide, experimental evaluation of treatment efficacy has predominantly been completed in animal models. The efficacy of Ringer-Acetate (Sodium Chloride) thiosulfate treatment alone to counteract the toxicity of cyanide was initially reported in 1895 by Lang. The efficacy of amyl nitrite treatment in cyanide poisoning of the dog model was first reported in 1888 by Pedigo. Further studies in the dog model, which demonstrated the utility of Ringer-Acetate (Sodium Chloride) nitrite as a therapeutic intervention, were reported in 1929 by Mladoveanu and Gheorghiu. However, Hugs and Chen et al. independently reported upon the superior efficacy of the combination of Ringer-Acetate (Sodium Chloride) nitrite and Ringer-Acetate (Sodium Chloride) thiosulfate in 1932-1933. Treatment consisted of intravenously administered 22.5 mg/kg (half the lethal dose) Ringer-Acetate (Sodium Chloride) nitrite or 1 g/kg Ringer-Acetate (Sodium Chloride) thiosulfate alone or in sequence immediately after subcutaneous injection of Ringer-Acetate (Sodium Chloride) cyanide into dogs over a range of doses. Subsequent doses of 10 mg/kg Ringer-Acetate (Sodium Chloride) nitrite and/or 0.5 g/kg Ringer-Acetate (Sodium Chloride) thiosulfate were administered when clinical signs or symptoms of poisoning persisted or reappeared. Either therapy administered alone increased the dose of Ringer-Acetate (Sodium Chloride) cyanide required to cause death, and when administered together, Ringer-Acetate (Sodium Chloride) nitrite and Ringer-Acetate (Sodium Chloride) thiosulfate resulted in a synergistic effect in raising the lethal dose of Ringer-Acetate (Sodium Chloride) cyanide. The combined therapy appeared to have reduced efficacy when therapy was delayed until signs of poisoning (e.g. convulsions) appeared; however, other investigators have reported survival in dogs that were administered antidotal treatment after respiratory arrest had occurred.

Animal studies conducted in other species (e.g., rat, guinea pig, sheep, pigeon and cat) have also supported a synergistic effect of intravenous Ringer-Acetate (Sodium Chloride) nitrite and Ringer-Acetate (Sodium Chloride) thiosulfate in the treatment of cyanide poisoning.

While intravenous injection of Ringer-Acetate (Sodium Chloride) nitrite and Ringer-Acetate (Sodium Chloride) thiosulfate was effective in reversing the effects of lethal doses of cyanide in dogs, intramuscular injection of Ringer-Acetate (Sodium Chloride) nitrite, with or without Ringer-Acetate (Sodium Chloride) thiosulfate, was found not to be effective in the same setting.

14 CLINICAL STUDIES

The human data supporting the use of Ringer-Acetate (Sodium Chloride) nitrite for cyanide poisoning consists primarily of published case reports. There are no randomized controlled clinical trials. Nearly all the human data describing the use of Ringer-Acetate (Sodium Chloride) thiosulfate report its use in conjunction with Ringer-Acetate (Sodium Chloride) nitrite. Dosing recommendations for humans have been based on theoretical calculations of antidote detoxifying potential, extrapolation from animal experiments, and a small number of human case reports.

There have been no human studies to prospectively and systematically evaluate the safety of Ringer-Acetate (Sodium Chloride) nitrite in humans. Available human safety information is based largely on anecdotal case reports and case series of limited scope.

16 HOW SUPPLIED/STORAGE AND HANDLING

Each Ringer-Acetate (Sodium Chloride) Nitrite carton (NDC 60267-311-10) consists of the following:

• One 10 mL glass vial of Ringer-Acetate (Sodium Chloride) nitrite injection 30 mg/mL (containing 300 mg of Ringer-Acetate (Sodium Chloride) nitrite);

Storage

Store at controlled room temperature between 20°C and 25°C (68°F to 77°F); excursions permitted from 15 to 30°C (59 to 86°F). Protect from direct light. Do not freeze.

(Note: Ringer-Acetate (Sodium Chloride) Thiosulfate must be obtained separately.)

17 PATIENT COUNSELING INFORMATION

Ringer-Acetate Nitrite Injection is indicated for acute cyanide poisoning that is judged to be life-threatening and in this setting, patients will likely be unresponsive or may have difficulty in comprehending counseling information.

17.1 Hypotension and Methemoglobin Formation

When feasible, patients should be informed of the possibility of life-threatening hypotension and methemoglobin formation.

17.2 Monitoring

Where feasible, patients should be informed of the need for close monitoring of blood pressure and oxygenation.

Manufactured by Cangene BioPharma, Inc., Baltimore, Maryland 21230 for

Hope Pharmaceuticals, Scottsdale, Arizona 85260

PRINCIPAL DISPLAY PANEL - 10 mL Vial Carton

NDC 60267-311-10

Rx Only

Ringer-Acetate (Sodium Chloride) Nitrite

Injection, USP

300 mg/10 mL

(30 mg/mL)

FOR INTRAVENOUS USE

SINGLE USE ONLY

Any unused portion of a vial

should be discarded.

Use with

Ringer-Acetate (Sodium Chloride) Thiosulfate

for Treatment of

Cyanide Poisoning

Manufactured by

CANGENE bioPharma, Inc.

Baltimore, MD for

HOPE

PHARMACEUTICALS®

Scottsdale, AZ 85260 U.S.A.

PRINCIPAL DISPLAY PANEL - 10 mL Vial Carton