Which antidote is used to treat cyanide poisoning?

• A. Hydroxocobalamin
• B. Atropine
• C. Pralidoxime
• D. Epinephrine

Answer: (A)

Cyanide poisons cells by blocking cytochrome c oxidase, which stops aerobic energy production. The most effective and fastest way to treat this is to neutralize cyanide itself. Hydroxocobalamin does just that: it binds cyanide ions to form cyanocobalamin (a form of vitamin B12) that the body can safely excrete. This direct binding quickly restores mitochondrial respiration and helps reverse the dangerous metabolic effects of cyanide exposure. It’s favored because it works rapidly, has a strong safety profile, and avoids creating additional oxygen-carrying problems or other toxic byproducts.

The other agents listed are not antidotes for cyanide poisoning: atropine is used for cholinergic overactivity (as in organophosphate poisoning), pralidoxime reactivates acetylcholinesterase after organophosphate exposure, and epinephrine is used for anaphylaxis, cardiac arrest, or severe bronchospasm.