Polymorphism of dextromethorphan oxidation in Polish population.

Determination of oxidation phenotype is used to obtain the best results of pharmacotherapy and to explain a lower efficiency of some drugs in particular patients. The purpose of the present study was to determine the distribution of CYP2D6 metabolizer status in subjects from central Poland, using dextromethorphan as the probe drug. The study included 104 healthy Polish volunteers. All subjects received a single oral dose of 40 mg of dextromethorphan and the complete urine output was collected over a period of 10 h. DM and the metabolite dextrorphan (DT) were analyzed by HPLC method. The results of a Polish population study revealed a bimodal distribution of the dextromethorphan metabolic ratio and showed the existence of two oxidation phenotypes as extensive (EM) and poor (PM) metabolizers. In our population, the frequency of the PM phenotype was 9.6%. The results obtained (9.6% of PM phenotype) were in accordance with other results obtained in Poland and other Caucasian populations.