A population study of the frequency of high-dose acetaminophen prescribing and dispensing.

Background: Recurrent intake of 4 g/day or more of acetaminophen has been associated with elevation of serum alanine aminotransferase (ALT) levels in 30-40% of the exposed population and may result in hepatotoxicity.

Objective: To describe the frequency that patients are prescribed acetaminophen doses that exceed 4 g/day across a large population.

Methods: Using California's Medicaid (Medi-Cal) fee-for-service population, pharmacy claims including over-the-counter (OTC) medications were examined for prescriptions that could result in acetaminophen doses of 4 g/day or more.