Acute Liver Injury With Therapeutic Doses of Acetaminophen: A Prospective Study.

Background And Aims: Because of the extensive use of this drug, further evaluation of acute liver injury (ALI) with therapeutic doses of acetaminophen (APAP; ≤6 g/d) is required. We characterize ALI with therapeutic doses of APAP and determine the host factors associated with disease severity and the predictors of outcome.

Approach And Results: All patients admitted with severe APAP-related ALI in our center were included from 2002 to 2019, either attributable to therapeutic doses or overdose. ALI with therapeutic doses (ALITD) was defined as APAP intake <6 g/d. Overall, 311 of 400 patients with APAP-related ALI had overdose and 89 had taken therapeutic doses. The host factors associated with ALITD were fasting ≥1 day (47.5% of ALITD patients vs. 26% in overdose; P = 0.001), excess drinking (93.3% vs. 48.5%; P < 0.0001), and repeated APAP use (4 vs. 1 day; P < 0.0001). Patients with ALITD were older (44 vs. 30.7 years; P < 0.0001) and had more severe liver injury. In the overall population, the independent predictors of disease severity were older age, longer duration of APAP, and excess drinking. Thirty-day survival was lower in ALITD than in overdose (87.2 ± 3.6% vs. 94.6 ± 1.3%; P = 0.02). Age and the presence of at least one of the King's College Hospital criteria were independent predictors of 30-day survival whereas the pattern of drug intoxication, excess drinking, and bilirubin were not.

Conclusions: ALI with therapeutic doses of APAP is associated with more severe liver injury than overdose. It only occurs in patients with excess drinking and/or fasting. A warning should be issued about the repeated use of nontoxic doses of APAP in patients with those risk factors.