The antidote of choice in paracetamol poisoning is :
**Core Concept**
The management of paracetamol (acetaminophen) poisoning involves the use of an antidote to prevent or treat liver damage caused by the toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI). The antidote works by replenishing the body's stores of glutathione, a crucial antioxidant that neutralizes NAPQI.
**Why the Correct Answer is Right**
The antidote of choice in paracetamol poisoning is **N-acetylcysteine (NAC)**, which replenishes glutathione levels and helps to conjugate and render NAPQI harmless. NAC also has a sulfhydryl group that directly scavenges NAPQI, further reducing its toxic effects on the liver. The mechanism of action involves the regeneration of glutathione stores, which in turn inhibits the formation of NAPQI and other toxic metabolites that contribute to liver damage.
**Why Each Wrong Option is Incorrect**
* **Option A:** Activated charcoal may be used to prevent the absorption of paracetamol in the gut, but it does not have any direct effect on the toxic metabolites that cause liver damage.
* **Option B:** Fomepizole is used as an antidote in methanol and ethylene glycol poisoning, not paracetamol poisoning.
* **Option C:** Flumazenil is a benzodiazepine antagonist used to reverse benzodiazepine overdose, and is not relevant to the treatment of paracetamol poisoning.
**Clinical Pearl / High-Yield Fact**
In patients with paracetamol poisoning, early administration of NAC within 8-10 hours of ingestion significantly improves outcomes and reduces the risk of liver failure.
**Correct Answer:** N-acetylcysteine (NAC)