Pharmacokinetics of acetaminophen in Hong Kong Chinese subjects

The pharmacokinetics of acetaminophen have been well studied in different populations, especially in Caucasians. However, limited studies on acetaminophen pharmacokinetics have been conducted in the native Chinese and few such data have been reported in the English language literature. Previous published studies suggested that environmental and genetic factors may cause inter-individual difference in acetaminophen disposition, thus we investigated the pharmacokinetics of acetaminophen in Hong Kong Chinese subjects. A single 500 mg oral dose of acetaminophen was administered to 12 healthy male Chinese subjects under fasting conditions. Multiple blood samples were obtained after drug administration. Plasma acetaminophen concentrations were determined using HPLC, and its main pharmacokinetic parameters were generated. In comparison to other published data, acetaminophen half-life was considerably longer (15-62%), and oral clearance was lower (16-56%) in Hong Kong Chinese as compared to Australian Chinese, Caucasians (USA, UK, Australia), and subjects from Pakistan, Denmark, Spain and South Africa. Similarities however were found in the pharmacokinetic parameters between Hong Kong Chinese and Mainland Chinese subjects. The observed pharmacokinetic parameters of acetaminophen in Hong Kong Chinese subjects may be different from other ethnic populations. Further studies are needed to verify this hypothesis.