Patient MOLN arrives at the hospital and complains of mild gastrointestinal upset. Later, it was found to be caused by APAP poisoning. What is the antidote of choice for APAP poisoning?

• A. N-acetylcysteine
• B. Phytomenadione
• C. Flumazenil
• D. Sodium bicarbonate

Answer: (A)

Acetaminophen overdose causes liver injury when the toxic metabolite NAPQI builds up after glutathione stores are overwhelmed. N-acetylcysteine is the antidote of choice because it replenishes glutathione, allowing the body to detoxify NAPQI and protect liver cells. It can also directly scavenge some reactive intermediates, reducing damage. Because patients may feel only mild symptoms initially, starting NAC promptly when APAP poisoning is suspected is key to preventing hepatotoxicity and long-term injury. Other listed agents do not counteract acetaminophen toxicity—vitamin K reverses bleeding risks, flumazenil reverses benzodiazepines, and sodium bicarbonate treats different conditions—not APAP poisoning.