Sodium Nitrite And Sodium Thiosulfate

FDA Drug Information • Also known as: Nithiodote

Brand Names: Nithiodote
Dosage Form: KIT
Product Type: HUMAN PRESCRIPTION DRUG

⚠ Boxed Warning (Black Box)

WARNING: LIFE THREATENING HYPOTENSION AND METHEMOGLOBIN FORMATION Sodium nitrite can cause serious adverse reactions and death in humans, even at doses less than twice the recommended therapeutic dose. Sodium nitrite causes hypotension and methemoglobin formation, which diminishes oxygen carrying capacity. Hypotension and methemoglobin formation can occur concurrently or separately. Because of these risks, sodium nitrite should be used to treat acute life-threatening cyanide poisoning and be used with caution in patients where the diagnosis of cyanide poisoning is uncertain . Patients should be closely monitored to ensure adequate perfusion and oxygenation during treatment with sodium nitrite. Alternative therapeutic approaches should be considered in patients known to have diminished oxygen or cardiovascular reserve (e.g. smoke inhalation victims, pre-existing anemia, cardiac or respiratory compromise), and those at higher risk of developing methemoglobinemia (e.g., congenital methemoglobin reductase deficiency) as they are at greater risk for potentially life-threatening adverse events related to the use of sodium nitrite . [See Warnings and Precautions (5.1 and 5.2) ] WARNING: LIFE-THREATENING HYPOTENSION AND METHEMOGLOBIN FORMATION See full prescribing information for complete boxed warning . Sodium nitrite can cause serious adverse reactions and death from: Hypotension ( 5.1 ) Methemoglobin formation ( 5.2 ) Patients should be closely monitored to ensure adequate perfusion and oxygenation during treatment with sodium nitrite.

Description

11 DESCRIPTION Sodium nitrite, one of the active ingredients in NITHIODOTE has the chemical name nitrous acid sodium salt. The chemical formula is NaNO 2 and the molecular weight is 69.0. Sodium thiosulfate, the second active ingredient in NITHIODOTE has the chemical name thiosulfuric acid, disodium salt, pentahydrate. The chemical formula is Na 2 S 2 O 3 ∙ 5H 2 O and the molecular weight is 248.17. The structural formulae are: Structure of Sodium Nitrite Structure of Sodium Thiosulfate Pentahydrate NITHIODOTE is a cyanide antidote which contains one 10 mL glass vial of a 3% solution of sodium nitrite injection and one 50 mL glass vial containing a 25% solution of sodium thiosulfate injection. Sodium nitrite injection is a sterile aqueous solution and is intended for intravenous injection. Each vial contains 300 mg of sodium nitrite in 10 mL solution (30 mg/mL). Sodium nitrite injection is a clear solution with a pH between 7.0 and 9.0. Sodium thiosulfate injection is a sterile aqueous solution and is intended for intravenous injection. Each vial contains 12.5 grams of sodium thiosulfate in 50 mL solution (250 mg/mL). Each mL also contains 2.8 mg boric acid and 4.4 mg of potassium chloride. The pH of the solution is adjusted with boric acid and/or sodium hydroxide. Sodium thiosulfate injection is a clear solution with a pH between 7.5 and 9.0. Chemical Structure Chemical Structure

What Is Sodium Nitrite And Sodium Thiosulfate Used For?

1 INDICATIONS AND USAGE NITHIODOTE is indicated for the treatment of acute cyanide poisoning that is judged to be serious or life-threatening. When the diagnosis of cyanide poisoning is uncertain, carefully weigh the potentially life-threatening risks associated with NITHIODOTE against the potential benefits, especially if the patient is not in extremis. NITHIODOTE, an antidote, is indicated for the treatment of acute cyanide poisoning that is judged to be serious or life-threatening. ( 1 ) Use with caution if the diagnosis of cyanide poisoning is uncertain. ( 1 )

Dosage and Administration

2 DOSAGE AND ADMINISTRATION If clinical suspicion of cyanide poisoning is high, administer NITHIODOTE without delay and in conjunction with appropriate airway, ventilatory, and circulatory support. ( 2.1 ) The expert advice of a regional poison control center may be obtained by calling 1-800-222-1222. ( 2.1 ) Dosing : Age Intravenous Dose of Sodium Nitrite and Sodium Thiosulfate Adults 1) Sodium Nitrite -10 mL of sodium nitrite at the rate of 2.5 to 5 mL/minute 2) Sodium Thiosulfate - 50 mL of sodium thiosulfate immediately following administration of sodium nitrite. Children 1) Sodium Nitrite - 0.2 mL/kg (6 mg/kg or 6-8 mL/m 2 BSA) of sodium nitrite at the rate of 2.5 to 5 mL/minute not to exceed 10 mL 2) Sodium Thiosulfate - 1 mL/kg of body weight (250 mg/kg or approximately 30-40 mL/m 2 of BSA) not to exceed 50 mL total dose immediately following administration of sodium nitrite. Redosing : If signs of cyanide poisoning reappear, repeat treatment using one-half the original dose of both sodium nitrite and sodium thiosulfate. ( 2.2 ) Monitoring : Blood pressure must be monitored during treatment. ( 2.2 ) NITHIODOTE is chemically incompatible with hydroxocobalamin and should not be administered via the same intravenous line. ( 2.4 ) 2.1 Important Dosage and Administration Instructions If clinical suspicion of cyanide poisoning is high, administer NITHIODOTE without delay. Comprehensive treatment of acute cyanide intoxication requires support of vital functions. Administration of sodium nitrite and sodium thiosulfate should be considered adjunctive to appropriate supportive therapies. Airway, ventilatory and circulatory support, and oxygen administration should not be delayed in order to administer sodium nitrite and sodium thiosulfate [see Warnings and Precautions (5.1) ] . The expert advice of a regional poison control center may be obtained by calling 1-800-222-1222. 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 sodium 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. Table 1. Common Signs and Symptoms of Cyanide Poisoning Symptoms Signs Headache Confusion Dyspnea Chest Tightness Nausea Altered Mental Status (e.g., confusion, disorientation) Seizures or Coma Mydriasis Tachypnea/Hyperpnea (early) Bradypnea/Apnea (late) Hypertension (early)/ Hypotension (late) Cardiovascular Collapse Vomiting Plasma Lactate Concentration ≥ 8 mmol/L In some settings, panic symptoms including tachypnea and vomiting may mimic early cyanide poisoning signs. The...

Side Effects (Adverse Reactions)

6 ADVERSE REACTIONS There have been no controlled clinical trials conducted to systematically assess the adverse events profile of sodium nitrite or sodium thiosulfate. The medical literature has reported the following adverse events in association with sodium nitrite or sodium thiosulfate 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. Most common adverse reactions are: Sodium nitrite : syncope, hypotension, tachycardia, palpitations, dysrhythmia, methemoglobinemia, headache, dizziness, blurred vision, seizures, confusion, coma ( 6 ) Sodium thiosulfate : hypotension, headache, disorientation ( 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 . S odium Nitrite 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 sodium nitrite at doses less than twice those recommended for the treatment of cyanide poisoning. Sodium Thiosulfate Cardiovascular system: hypotension Central nervous system: headache, disorientation Gastrointestinal system: nausea, vomiting Hematological : prolonged bleeding time Body as a Whole: salty taste in mouth, warm sensation over body In humans, rapid administration of concentrated solutions or solutions not freshly prepared, and administration of large doses of sodium thiosulfate have been associated with a higher incidence of nausea and vomiting. However, administration of 0.1 g sodium thiosulfate per pound up to a maximum of 15 g in a 10-15% solution over 10-15 minutes was associated with nausea and vomiting in 7 of 26 patients without concomitant cyanide intoxication. In a series of 11 human subjects, a single intravenous infusion of 50 mL of 50% sodium thiosulfate was associated with increases in clotting time 1-3 days after administration. However, no significant changes were observed in other hematological parameters.

Drug Interactions

7 DRUG INTERACTIONS Formal drug interaction studies have not been conducted with NITHIODOTE.

Contraindications

4 CONTRAINDICATIONS None None. ( 4 )

Pregnancy and Breastfeeding

8.1 Pregnancy Risk Summary Life-sustaining therapy should not be withheld. Cyanide poisoning is a medical emergency in pregnancy, which can be fatal for the pregnant woman and fetus if left untreated (see Clinical Considerations ). Therefore, if a pregnant woman has known or suspected cyanide poisoning, Sodium Nitrite Injection for sequential use with Sodium Thiosulfate Injection is recommended [see Indications and Usage (1) ]. There are no available data on NITHIODOTE use in pregnant women to establish a drug-associated risk for major birth defects, miscarriage, or adverse maternal or fetal outcomes. If available, consider alternative therapies not associated with methemoglobinemia. There are no intravenous animal studies to evaluate the effect of sodium nitrite, sodium thiosulfate, or the combination on embryofetal development. In published animal studies, fetal mortality was reported when pregnant guinea pigs were subcutaneously administered sodium nitrite at 1.7 times the maximum recommended human dose (MRHD) of 450 mg sodium nitrite when maternal and fetal methemoglobin concentrations were at their peak. In other published studies, no evidence of malformations were reported in guinea pigs, mice, or rats; however, severe anemia, reduced growth, and increased pup mortality was reported when pregnant rats were treated with 4.7 times the MRHD of sodium nitrite via drinking water during gestation and throughout lactation. In published animal studies, no evidence of embryotoxicity or malformations was reported when sodium thiosulfate was administered orally during organogenesis to pregnant mice, rats, hamsters, or rabbits at 0.2 to 0.9 times the human daily dose of 12.5 g for cyanide poisoning. The sodium thiosulfate studies did not test doses that were comparable to the human dose for cyanide poisoning (see Data ). Clinical Considerations Disease-associated maternal and/or embryo/fetal risk Cyanide readily crosses the placenta. Cyanide poisoning is a medical...

Overdosage

10 OVERDOSAGE Sodium Nitrite Large doses of sodium nitrite result in severe hypotension and toxic levels of methemoglobin which may lead to cardiovascular collapse. Sodium 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 sodium 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 sodium 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. Sodium Thiosulfate There is limited information about the effects of large doses of sodium thiosulfate in humans. Oral administration of 3 g sodium thiosulfate per day for 1-2 weeks in humans resulted in reductions in room air arterial oxygen saturation to as low as 75%, which was due to a rightward shift in the oxygen hemoglobin dissociation curve. The subjects returned to baseline oxygen saturations 1 week after discontinuation of sodium thiosulfate. A single intravenous administration of 20 mL of 10% sodium thiosulfate reportedly did not change oxygen saturations.

How Supplied

16 HOW SUPPLIED/STORAGE AND HANDLING Each NITHIODOTE carton (NDC 60267-812-00) consists of the following: One 10 mL glass vial of sodium nitrite injection 30 mg/mL (containing 300 mg of sodium nitrite); One 50 mL glass vial of sodium thiosulfate injection 250 mg/mL (containing 12.5 grams of sodium thiosulfate); One package insert. Storage Store at controlled room temperature between 20°C and 25°C (68°F - 77°F); excursions permitted to 15-30°C (59 to 86°F). Protect from direct light. Do not freeze.

About This Information

This drug information is sourced from FDA-approved labeling via the openFDA database. It is intended for educational and reference purposes only. This is not medical advice. Always consult your healthcare provider before making decisions about medication. Drug information may be updated by the FDA; check with your pharmacist for the most current information.

What are side effects?

Side effects are unwanted reactions that can occur when taking a medication. They range from mild (headache, nausea) to severe (allergic reactions, organ damage). Not everyone experiences side effects, and severity varies. Report any concerning side effects to your doctor.

What are drug interactions?

Drug interactions occur when a medication is affected by another drug, food, or supplement. Interactions can make medications less effective or cause dangerous side effects. Always tell your doctor about all medications and supplements you take.