Last reviewed 2026-04-20 · How we verify

Sodium Nitrite (SODIUM NITRITE)

Sodium nitrite works by converting hemoglobin to methemoglobin, which binds to cyanide and prevents it from interfering with cellular respiration.

At a glance

Mechanism of action

Exposure to 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, component of the cytochrome 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 sodium nitrite and sodium thiosulfate is the result of differences in their primary mechanisms of action as antidotes for cyanide poisoning.. Sodium NitriteSodium 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 affi

Approved indications

• Toxic effect of cyanide

Boxed warnings

• 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.

Common side effects

• Syncope
• Hypotension
• Tachycardia
• Palpitations
• Dysrhythmia
• Methemoglobinemia
• Seizures
• Confusion
• Coma
• Headache
• Dizziness
• Blurred vision

Key clinical trials

• Effect of Sublingually Generated S-nitroso-N-acetylcysteine on Systemic Blood Pressure. (EARLY_PHASE1)
• Effects of Sustained-release Oral Sodium Nitrite on Postoperative Pain and Recovery Following Total Knee Arthroplasty (PHASE1)
• Topical Sodium Nitrite in Sickle Cell Disease and Leg Ulcers (PHASE2)
• Preventing Pulmonary Complications in Surgical Patients at Risk of COVID-19 (PHASE3)
• Assessment of KM-001 - Safety, Tolerability, and Efficacy in Patients With PPPK1 or PC (PHASE1)
• Study Designed to Evaluate Safety and Efficacy of 1% Topical Formulation of KM-001 on Type 1 Punctate Palmoplantar Keratoderma or Pachyonychia Congenita Diseases (PHASE1)
• Nitrites, Skeletal Muscle Mitochondrial Bioenergetics, and Physical Activity in Old Age (PHASE2)
• Inhaled Sodium Nitrite as an Antimicrobial for Cystic Fibrosis (PHASE1,PHASE2)

Patents

Primary sources

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Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Sodium Nitrite CI brief — competitive landscape report
• Sodium Nitrite updates RSS · CI watch RSS
• Hope Pharms portfolio CI