CYP2D6 phenotyping with dextromethorphan.

Area of Science:

• Pharmacogenomics
• Drug Metabolism

Background:

• Genetic variations influence drug oxidation, impacting pharmacotherapy efficacy and safety.
• Cytochrome P450 2D6 (CYP2D6) phenotype determination is crucial for personalized medicine.
• Understanding individual drug metabolism aids in preventing adverse drug reactions and optimizing treatment.

Purpose of the Study:

• To identify the CYP2D6 oxidation phenotype in a healthy Polish population.
• To utilize dextromethorphan (DM) as a probe drug for CYP2D6 phenotyping.
• To establish the frequency of different CYP2D6 metabolic phenotypes in the studied cohort.

Main Methods:

• A study involving 85 healthy adult volunteers of Polish origin.
• Oral administration of 40 mg dextromethorphan (DM) followed by 10-hour urine collection.
• Analysis of DM and its metabolite dextrorphan (DX) using High-Performance Liquid Chromatography (HPLC).
• Phenotyping based on the metabolic ratio (MR) of urinary DM/DX output.

Main Results:

• The metabolic ratio (MR) was calculated to classify individuals as extensive metabolizers (EM) or poor metabolizers (PM).
• Individuals with a dextromethorphan MR > 0.3 were classified as PMs.
• The frequency of the poor metabolizer (PM) phenotype was found to be 9.4% in the Polish cohort.

Conclusions:

• The prevalence of CYP2D6 poor metabolizers in the Polish population is 9.4%.
• This frequency is consistent with the reported range (3-10%) observed in other Caucasian populations.
• These findings contribute to understanding pharmacogenetic variations relevant to drug therapy in this demographic.