Patterns of acetaminophen use exceeding 4 grams daily in a hospitalized population at a tertiary care center

Unintentional acetaminophen-induced hepatotoxicity has been increasingly recognized as a significant problem, prompting increased scrutiny and restrictions from the US Food and Drug Administration on products combining acetaminophen with narcotics. Patterns of acetaminophen use have not previously been reported in the hospitalized patient population, which may be especially vulnerable to liver injury. We aimed to quantify the frequency at which acetaminophen dosing exceeded the recommended maximum of 4 g/day in hospitalized patients. This was a retrospective, single-center, cohort study at a large tertiary care academic hospital. We queried our inpatient electronic medical record database to identify patients admitted between 2008 and 2010 who were receiving cumulative daily acetaminophen doses exceeding 4 g on at least 1 hospital day. Of 43,761 admissions involving acetaminophen administration, the recommended maximum cumulative daily dose of 4 g was exceeded in 1119 (2.6%) cases. Patients who were administered a larger number of acetaminophen-containing medications were more likely to receive doses in excess of the recommended maximum. Alanine aminotransferase (ALT) levels were checked within 14 days following acetaminophen exposure in excess of 4 g in 35 (3.1%) cases. Excessive acetaminophen dosing of hospitalized patients, who may be at increased risk for acetaminophen-induced hepatotoxicity, occurred in a minority of patients. The use of multiple acetaminophen-containing medication formulations contributed to excessive dosing. ALT level monitoring in this group was infrequent, precluding assessment of biochemical evidence of liver injury. This cohort of patients may represent an ideal population for further prospective study with more intensive and longer-term biochemical monitoring to assess for evidence of liver injury.