What is the antidote for acetaminophen overdose?

• A. Activated charcoal
• B. Naloxone
• C. N-acetylcysteine (NAC)
• D. Flumazenil

Answer: (C)

In acetaminophen overdose, the dangerous step is the formation of NAPQI, a toxic metabolite that depletes the liver’s glutathione and damages hepatocytes. N-acetylcysteine is the antidote because it replenishes glutathione stores and also acts as a precursor that helps detoxify NAPQI, effectively preventing or reducing liver injury. It can be given orally or by IV and is most beneficial when started early, ideally within 8–10 hours of ingestion, though it can still help later depending on levels and timing. Activated charcoal can reduce absorption if given soon after ingestion, but it is not the antidote itself. Naloxone and flumazenil reverse opioid and benzodiazepine effects, respectively, and are not indicated for acetaminophen toxicity.