The influence of CYP2D6 activity on the kinetics of propafenone enantiomers in Chinese subjects

Aims To determine role of CYP2D6 activity in the pharmacokinetics of propafenone (PPF) enantiomers in native Chinese subjects. Methods Sixteen extensive metabolizers (EMs) and one poor metabolizer (PM), whose phenotype had been previously assessed with dextromethorphan metabolic phenotyping, were enrolled. Blood samples (0~15 h) were taken after oral administration of a single dose (400 mg) of racemic‐propafenone hydrochloride. A reverse‐phase h.p.l.c. method with pre‐column derivatization was employed to quantitate enantiomeric concentrations of propafenone in plasma. Results For the EM subjects, S‐PPF was less rapidly metabolized and had higher peak plasma concentrations than R‐PPF (413±143 vs 291±109 ng ml−1, P