Amyl nitrite, cyanide poisoning treatment

Treatment — Patients should be decontaminated immediately prior to treatment using the decontamination method presented in Section 7.3.3. The Lilly Cyanide Antidote Kit contains amyl nitrite, sodium nitrite, and sodium thiosulfate. Dimeth-ylaminophenol, cobalt-edetate, or vitamin B12a are alternative antidotes for cyanide poisoning.5... 

Treatment of cyanide poisoning includes rapid administration of activated charcoal (although charcoal binds cyanide poorly, it can reduce absorption) and general supportive care. The conventional antidote kit available in the USA includes two forms of nitrite (amyl nitrite and sodium nitrite) and sodium thiosulfate. The nitrites induce methemoglobinemia, which binds to free CI T creating the less toxic cyanomethemoglobin thiosulfate is a cofactor in the enzymatic conversion of CN to the much less toxic thiocyanate (SCINT). Recently, the FDA approved a concentrated form of hydroxocobalamin, which is now available as the Cyanokit (EMD Pharmaceuticals, Durham, North Carolina). Hydroxocobalamin (one form of vitamin B12) combines rapidly with CN to form cyanocobalamin (another form of vitamin B12). 

Sodium nitrite or amyl nitrite can be used in cyanide poisoning. They promote formation of methemoglobin, which binds CN" ions, forming cyanomethemoglobin. This prevents the inhibitory action of CN on complex IV of the electron transport chain. Cyanomethemoglobin is then reconverted to methemoglobin by treatment with sodium thiosulfate, forming the less toxic thiocyanate ion (SCN ). 

Amyl nitrate is an effective antidote against cyanide poisoning. The treatment involves artificial respiration, followed by inhalation of amyl nitrite. In severe poisoning, intra-venons administration of sodium nitrite, followed by sodinm thiosnlfate is given. The dose is 0.3 g of NaN02 (10 mL of a 3% solution at a rate of 2-5 mL/min) and 25 g of Na2S203 (50 mL of a 25% solution at a rate of 2-5 mL/min) (Hardy and Boylen 1983). 

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