Substance
Cyanide

Pathology
Nonspecific inhibition of enzyme systems; binds to cytochrome oxidase of cells, blocking oxygen use.

Symptoms
Nausea, vomiting, abdominal pain, almond odor of breath, headache, dyspnea, agitation, confusion, syncope, convulsions, lethargy, coma, cardiovascular collapse, death. Onset of symptoms is abrupt.

Emergency Measures
Oxygen and assisted ventilation, if needed; gastric lavage, activated charcoal, and cathartic; inhalation of amyl nitrite pearls until antidote is available. Antidote kit contains amyl and sodium nitrites and sodium thiosulfate. The administration of vitamin B₁₂ may be helpful.

Comments
Oxygen and assisted ventilation, if needed; activated charcoal by mouth. Antidotes include amyl and sodium nitrites and sodium thiosulfate. Vitamin B₁₂ may also be used.