Which drug is used as an antidote for acetaminophen overdose?

N-acetylcysteine (NAC) is the specific antidote used for acetaminophen overdose. It works primarily by replenishing glutathione stores in the liver, which helps detoxify the harmful metabolites of acetaminophen. In cases of overdose, the liver can become overwhelmed by the toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI), leading to hepatotoxicity. NAC serves to either directly conjugate with NAPQI to form a non-toxic compound or to restore glutathione levels so that it can neutralize NAPQI, thereby preventing or mitigating liver damage.

NAC administration is most effective when given within 8 to 10 hours of the acetaminophen overdose; however, it can still provide benefits even when given later. The use of NAC is well-established and is a critical component of the management protocol in emergency settings for acetaminophen toxicity.