What is the antidote for acetaminophen poisoning?

N-acetylcysteine (NAC) is the antidote for acetaminophen poisoning because it replenishes glutathione, a vital antioxidant that helps the body detoxify harmful byproducts of acetaminophen metabolism. When acetaminophen is taken in excessive doses, it depletes glutathione stores, leading to toxic levels of a metabolite known as NAPQI, which can cause severe liver damage. NAC works by conjugating with NAPQI, which allows for its excretion and helps restore glutathione levels, thereby protecting the liver from damage.

In contrast, activated charcoal is often used as an emergency treatment to reduce absorption of various toxins but does not specifically target the mechanisms of acetaminophen toxicity. Atropine is an anticholinergic drug typically used for poisoning with organophosphates, while flumazenil is a benzodiazepine antagonist, used in cases of benzodiazepine overdose. Neither of these two is relevant in the context of acetaminophen poisoning.