sodium nitrite + sodium thiosulfate

**Sodium nitrite + sodium thiosulfate** is a fixed-dose combination medication used as an antidote for acute cyanide poisoning. This combination has been the primary cyanide antidote in the United States since the 1930s. The two components work synergistically through different mechanisms: **sodium nitrite** rapidly reacts with hemoglobin to form methemoglobin, which preferentially binds cyanide over cytochrome c oxidase, forming the non-toxic cyanomethemoglobin compound and displacing cyanide from mitochondrial cytochrome a3 to restore cellular respiration. **Sodium thiosulfate** serves as a sulfur donor for the enzyme rhodanese, facilitating the conversion of cyanide into thiocyanate, a relatively non-toxic compound that is eliminated in urine. The combination is administered sequentially as intravenous injections, with sodium nitrite given first followed by sodium thiosulfate. This dual-mechanism approach provides greater efficacy than either agent alone. The medication is indicated for life-threatening cyanide poisoning in both adults and children, which can occur from various exposures including smoke inhalation from fires, industrial accidents, and ingestion of cyanide-containing compounds.

Brand names

Nithiodote

Other names

sodium nitrite/sodium thiosulfate