What antidote is used for cyanide poisoning and what is the typical dose?

• A. Hydroxocobalamin 5 g IV; may be repeated
• B. Sodium nitrite 1 g IV; repeated
• C. Amyl nitrite inhalation
• D. N-acetylcysteine 140 mg/kg IV

Answer: (A)

Cyanide poisoning is treated with a scavenger that binds cyanide to form a non-toxic compound that the body can eliminate. Hydroxocobalamin does this by binding cyanide to make cyanocobalamin (vitamin B12), which is then excreted. The typical dose is 5 g given intravenously, usually over about 15 minutes. If cyanide effects persist or the exposure is severe, a second 5 g dose can be given, for a total of up to 10 g. A notable side effect is a red/orange discoloration of the skin and urine, which is harmless but can interfere with some lab tests. Other options like sodium nitrite or amyl nitrite work by inducing methemoglobinemia to bind cyanide but carry significant risks and are not preferred as first-line treatments. N-acetylcysteine is used for acetaminophen toxicity, not cyanide poisoning.