Clinical course of repeated supratherapeutic ingestion of acetaminophen

Abstract

Background: Repeated supratherapeutic ingestion (RSTI) of acetaminophen (APAP) is recognized as an important cause of APAP-related morbidity and mortality. This study describes the characteristics and clinical course of patients with RSTI, and identifies the risk factors for developing hepatotoxicity and death.

Methods: This secondary analysis of a multicenter retrospective chart review studied patients treated with IV and/or oral N-acetylcysteine for acetaminophen poisoning. For this analysis, we included all subjects coded as RSTIs, defined as ingestions of greater than 4 g of APAP per 24 h over a period longer than 8 h. Data collected include demographics, coingestants, comorbidities, presenting laboratory data, and outcomes. The analysis includes descriptive statistics and associations of demographic and clinical factors with patient outcome.

Results: Of the 503 patients enrolled, 119 (23.7%) were RSTI. The mean age was 39.6 years (SD ± 15); 63.9% of the patients were females, 60.5% Caucasians, 27.7% alcoholics, 5% malnourished, 10.9% had viral hepatitis, and 3.4% had other liver diseases. Coingestants included ethanol, opioids, and antihistamines (17.6, 48.7, and 19.3%, respectively). Among this group, 44 patients developed hepatotoxicity, two received liver transplants, and four died (37.0, 1.7, and 3.4%, respectively). The risk for hepatotoxicity increased with a history of alcoholism, viral hepatitis, and other liver diseases. A history of alcoholism and an elevated presenting serum creatinine were associated with increased risk for death/transplant. The lowest presenting ALT levels in a subject who developed hepatotoxicity and who died were 252 and 426 IU/l, respectively.

Conclusion: RSTI-induced hepatotoxicity and poor outcomes can be predicted at the patient's presentation. All patients with RSTI who developed hepatotoxicity presented with an abnormal ALT. A history of alcoholism and an elevated creatinine at presentation are markers of increased risk for hepatotoxicity and death.