In suspected cyanide poisoning, which treatment is recommended?

• A. Administer sodium thiosulfate.
• B. Initiate extracorporeal membrane oxygenation.
• C. Begin methylene blue infusion.
• D. Administer hydroxocobalamin.

Answer: (D)

In cyanide poisoning, the goal is to rapidly neutralize cyanide so cells can resume using oxygen. Hydroxocobalamin does this by binding cyanide to form cyanocobalamin, a harmless compound that is excreted in the urine. This makes it the preferred first-line antidote in EMS because it acts quickly and has a favorable safety profile, without needing the body to metabolize cyanide through other pathways. Sodium thiosulfate can help detoxify cyanide by converting it to thiocyanate, but this process is slower and less reliable in large or rapid exposures. Methylene blue is used for methemoglobinemia, not cyanide poisoning, and can complicate the situation. Extracorporeal membrane oxygenation is a supportive rescue therapy for severe cases but is not an antidote and requires specialized facilities. Therefore, administer hydroxocobalamin promptly. Typical dosing is about 5 g IV over 15 minutes, with repetition if needed.