Frequency distribution of dextromethorphan O-demethylation in a Greek population.

Objective: To determine the CYP2D6 phenotype in a Greek population by using dextromethorphan (DM) as a probe drug.

Methods: DM (30 mg) was given orally to 102 unrelated Greek subjects and 8-hour urine samples were collected. Concentrations of DM and its metabolite dextrorphan (DX) were determined using a validated HPLC assay.