Fomepizole is used for: CMC (Vellore) 14
**Core Concept**
Fomepizole is an antidote used in the management of ethylene glycol poisoning, acting as a competitive inhibitor of alcohol dehydrogenase, the enzyme responsible for the metabolism of ethylene glycol into its toxic metabolites.
**Why the Correct Answer is Right**
Fomepizole prevents the conversion of ethylene glycol into glycoaldehyde and oxalic acid, thereby reducing the risk of metabolic acidosis, renal failure, and calcium oxalate crystal formation. This mechanism of action is crucial in treating patients with ethylene glycol poisoning, as it allows for the reduction of toxic metabolites and subsequent clinical improvement. The use of fomepizole is particularly important in cases where the patient's condition is severe or when hemodialysis is not readily available.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because fomepizole is not primarily used for the treatment of methanol poisoning, although it can be used in some cases. Ethanol is the preferred antidote for methanol poisoning due to its ability to inhibit alcohol dehydrogenase and reduce the formation of formic acid.
**Option B:** This option is incorrect because fomepizole is not used as an antidote for acetaminophen overdose. N-acetylcysteine is the preferred antidote for acetaminophen poisoning, as it replenishes glutathione stores and reduces the risk of liver damage.
**Option C:** This option is incorrect because fomepizole is not used for the treatment of salicylate poisoning. Activated charcoal, hemodialysis, and sodium bicarbonate are used to manage salicylate poisoning, as they can help reduce the absorption and elimination of salicylates and correct acid-base disturbances.
**Clinical Pearl / High-Yield Fact**
Fomepizole is a high-yield topic in toxicology and is often tested in exams. It's essential to remember that fomepizole is a competitive inhibitor of alcohol dehydrogenase and is used in the treatment of ethylene glycol poisoning.
**Correct Answer: A. Fomepizole is used for treating ethylene glycol poisoning.**