The hepatic enzyme rhodanese catalyzes the one-way reaction of cyanide and a sulfane to thiocyanate. Sodium thiosulfate is packaged in a 50-mL ampule containing 12.5 grams of the drug. Intravenous injection of all 12.5 grams follows successful completion of the intravenous injection of sodium nitrite. Half of the original dosage of each drug may be repeated if symptoms persist. The Lilly Cyanide Antidote Kit, containing amyl nitrite, sodium nitrite, and sodium thiosulfate, is available to chemical depot medical facilities, military medical centers, and civilian facilities.
Supportive care consists of providing oxygen and correcting the metabolic acidosis.
There is no firm evidence to support the use of hyperbaric oxygen. Correction of the acidosis has helped cyanide-poisoned patients in whom the etiology was not recognized and to whom the antidote was not given. Other countries use different compounds. However, muscle necrosis at the site of injection occurs, and only the intravenous route of administration is recommended. Certain cobalt compounds directly chelate cyanide to reduce its toxicity.