1 learning resource available for this topic
Acetaminophen (paracetamol) overdose is one of the most common causes of acute liver failure in the United States and a leading reason for emergency department visits. Even doses that appear modest can be toxic in patients with underlying liver disease, chronic alcohol use, or malnutrition.
Toxic doses overwhelm the liver's glucuronidation and sulfation pathways, shunting metabolism toward the cytochrome P450 system. This produces a reactive metabolite (NAPQI) that depletes glutathione stores and causes direct hepatocellular necrosis, predominantly in the centrilobular zone.
Clinical reasoning centers on a time-drug-dose relationship. The Rumack-Matthew nomogram guides N-acetylcysteine (NAC) therapy based on serum acetaminophen levels drawn 4 hours post-ingestion. Key differentials include other causes of acute hepatocellular injury including viral hepatitis, ischemic hepatitis, and other drug-induced liver injury.