Dextromethorphan O-demethylation polymorphism in an African-American population.

Objective: One hundred eighty-one (97 F, 84 M) unrelated healthy African-American subjects (aged 18-41 years) were phenotyped based on their dextromethorphan (DMP) O-demethylation ability.

Methods: Each subject was given 15 mg DMP orally and collected 8-h urine. The concentrations of DMP and its metabolite dextrophan (DOP) were determined by HPLC with ultraviolet detection.