What is the antidote for cyanide poisoning?

• A. Sodium thiosulfate, hydroxocobalamin, nitrates
• B. Activated charcoal, acetylcysteine, benzodiazepines
• C. Dextrose, insulin, glucagon
• D. Flumazenil, naloxone, morphine

Answer: (A)

The antidote for cyanide poisoning primarily involves the use of sodium thiosulfate, hydroxocobalamin, and nitrates. Each of these agents works in distinct ways to counteract the toxic effects of cyanide.

Sodium thiosulfate serves as a substrate for the enzyme rhodanese, which converts cyanide to the less toxic thiocyanate, allowing it to be excreted in the urine. Hydroxocobalamin binds cyanide to form cyanocobalamin (vitamin B12), which is non-toxic and can be eliminated from the body. Nitrates help by inducing methemoglobinemia, which provides an alternative binding site for cyanide, removing it from its toxic action on cellular respiration.

These combined actions make the trio effective in managing cyanide toxicity, reinforcing why this option stands out as the appropriate antidote. Other options listed do not represent a valid treatment for cyanide poisoning.