sodium nitrite: clinical use

Prescribing considerations

• Use only when suspected acute cyanide poisoning is judged life-threatening; if the diagnosis is uncertain, balance antidotal benefit against potentially life-threatening toxicity.
• Treat as an adjunct to airway management, oxygenation, cardiovascular support, seizure management and exposure-appropriate decontamination.
• Exercise particular caution with smoke inhalation, carbon monoxide exposure, anaemia, substantial blood loss, or limited cardiac or respiratory reserve.
• Neonates and infants may be especially susceptible to severe methaemoglobinaemia.
• Consider alternatives in known G6PD deficiency because of haemolysis risk.

Contraindications and cautions

• Hypersensitivity to sodium nitrite or an excipient.

Monitoring

• Continuous clinical assessment of airway, ventilation, oxygenation and circulation
• Blood pressure during and after administration
• Methaemoglobin concentration where possible
• Haemoglobin or haematocrit, particularly with anaemia, blood loss or suspected G6PD deficiency
• Heart rhythm and neurological status

Clinical pharmacology

Sodium nitrite is an oxidant that converts haemoglobin to methaemoglobin, which binds cyanide preferentially over mitochondrial cytochrome oxidase. This can permit cellular respiration to resume, while sequential sodium thiosulfate enhances conversion of cyanide to thiocyanate.

Formulation and product differences

• The selected product is a clear, colourless solution for intravenous injection supplied in a single-use glass vial.
• Water for injections is the only listed excipient.
• Use after opening should be immediate; protect the unopened vial from light and inspect it before administration.
• Sodium nitrite and sodium thiosulfate may be given sequentially through the same line, but hydroxocobalamin must not be administered simultaneously through that line.