In the Emergency Department, we often screen for acetaminophen toxicity for patients who may have ingested substances as a suicide attempt. We check the serum acetaminophen level 4 hours post-ingestion. Occasionally, we are surprised by a toxic level because in the first 24 hours, because symptoms are can be mild and nonspecific (abdominal pain, nausea, lethargy).
- The toxic ingestion dose of acetaminophen is 150 mg/kg.
- The serum acetaminophen level when N-acetylcysteine treatment should be started is 150 mcg/mL (see Rumack Matthew nomogram)
- The starting IV dose of N-acetylcysteine is 150 mg/kg over 15 minutes.
Larson AM. Acetaminophen hepatotoxicity. Clin Liver Dis. 2007 Aug;11(3):525-48, vi. .