Background: Acetaminophen overdose is a frequent cause of acute liver failure. Controversy exists over the rare association of severe hepatotoxicity or acute liver failure with therapeutic doses of acetaminophen.
Case summary: A 45-year-old white man weighing 85 kg with asymptomatic HIV, hepatitis B virus, and hepatitis C virus (HCV) infection presented with signs of severe hepatotoxicity: aspartate aminotransferase (AST), 8,581 IU/L; alanine aminotransferase (ALT), 5,433 IU/L; L-lactate dehydrogenase, 13,641 IU/L; and prothrombin international normalized ratio, 2.15. He reported taking acetaminophen 1,000 mg QID for the previous 4 days and 1,000 mg that morning because of a febrile illness. Immediate administration of continuous IV N-acetylcysteine 150 mg/kg for the first 90 minutes and then 50 mg/kg q4h for the next 3 days was followed by clinical improvement and a rapid decrease in AST and ALT. AST levels decreased from 8,581 to 42 IU/L within 11 days. Several potential risk factors for acetaminophen hepatotoxicity (ie, chronic alcohol, tobacco, and opiate consumption, malnutrition, illness-induced starvation, HIV infection, and HCV infection) were present in this patient.
Conclusions: This patient with multiple risk factors and severe hepatotoxicity after therapeutic dosage of acetaminophen was successfully treated with N-acetylcysteine.