N-acetylcysteine (NAC, Mucomyst, Acetadote) is the antidote for acetaminophen toxicity. NAC restores hepatic glutathione and detoxifies NAPQI, the toxic metabolite. The Rumack-Matthew nomogram (using a 4-hour or later post-ingestion level) determines treatment thresholds. Maximum protection is achieved when NAC is started within 8 hours of ingestion; treatment is still beneficial up to 24 hours and beyond if hepatotoxicity has developed. Routes: IV (Acetadote) is preferred when the patient cannot tolerate oral, has GI bleeding, fulminant hepatic failure, or pregnancy; standard IV regimen is a 150 mg/kg loading dose over 60 minutes, then 50 mg/kg over 4 hours, then 100 mg/kg over 16 hours, with longer infusions if liver injury is established. Oral regimen is 140 mg/kg loading then 70 mg/kg every 4 hours for 17 doses; the strong sulfur (rotten egg) odor causes nausea — give with juice or carbonated drink, antiemetic, or NG tube. Sodium bicarbonate, charcoal alone after 4 hours, and naloxone do not address the hepatotoxic mechanism. Activated charcoal can adjunct within 1 to 2 hours of ingestion, not 6.
In-depth explanation
N-acetylcysteine ASAP, ideally within 8 hours, IV preferred for severe cases. The Rumack-Matthew nomogram drives the decision; do not wait for symptoms because hepatotoxicity is silent until day 2 to 4.
For study reference only. Always follow current clinical guidelines and your institution’s protocols.