VPT 421: Veterinary Toxicology (2+0)

ABSORPTION AND FATE

• HCN is rapidly absorbed from the intestinal tract and via the lungs.
• The gas is irritant to the mucous membrane.
• Some cyanide is also eliminated through the lungs, the exhaled air having a characteristic ‘Bitter almond’ smell.
• Cyanide is metabolized by rhodanase in the liver to thiocyanate. This reaction complexes cyanide with endogenous sulfur or sulfur supplied from the sodium thiosulfate antidote. Once thiocyanate is formed it is excreted mainly in the urine.

• Half-life for the metabolism of cyanide to thiocyanate is 20 min to 1 h. In animals, the dose of cyanide that produces signs is very close to the lethal dose and death can occur within seconds to minutes.