The antidote for APAP overdose is ______. It is almost ______% effective if given within ______ hours.

• A. NAC; 100; 8
• B. NAC; 50; 12
• C. Silymarin; 100; 6
• D. Glutathione; 25; 24

Answer: (A)

In acetaminophen overdose, the liver is injured by NAPQI, a toxic metabolite that depletes glutathione. N-acetylcysteine provides a ready source of cysteine to regenerate glutathione stores and directly helps detoxify NAPQI, preventing hepatocellular damage. When given early, within about 8 hours, NAC is highly effective—often described as nearly 100% protective against liver injury—because it preserves glutathione before extensive toxin binding occurs. Milk thistle (silymarin) has no proven antidote role here, and simply giving glutathione is not the standard approach; NAC is preferred because it efficiently replenishes the hepatic glutathione pool and supports detoxification.