Cyanide poisoning is treated by
**Core Concept**
Cyanide poisoning is a life-threatening condition caused by the inhibition of cellular respiration, resulting in the disruption of the electron transport chain and the production of ATP. This occurs due to the binding of cyanide to cytochrome c oxidase (Complex IV) in the mitochondrial electron transport chain.
**Why the Correct Answer is Right**
The treatment of cyanide poisoning involves the use of cyanide antidotes that act by either converting cyanide into a less toxic compound or by binding to cytochrome c oxidase and displacing cyanide. Hydroxocobalamin is a cyanide antidote that works by binding to cyanide and forming cyanocobalamin, which is then excreted in the urine. This reaction effectively reduces the concentration of free cyanide in the body and allows for the restoration of cellular respiration.
**Why Each Wrong Option is Incorrect**
**Option A:** Sodium thiosulfate is not a primary treatment for cyanide poisoning; it is often used in conjunction with hydroxocobalamin to enhance the excretion of cyanide.
**Option B:** Fomepizole is a treatment for methanol and ethylene glycol poisoning, not cyanide poisoning.
**Option C:** N-acetylcysteine is used to treat acetaminophen overdose, not cyanide poisoning.
**Clinical Pearl / High-Yield Fact**
It is essential to note that hydroxocobalamin should be administered in a well-ventilated area, as it can cause a red discoloration of the skin and mucous membranes due to the formation of cyanocobalamin.
**Correct Answer: D. Hydroxocobalamin**