Polymorphic debrisoquin metabolism in a Turkish population

Area of Science:

• Pharmacogenetics
• Drug Metabolism
• Population Genetics

Background:

• Debrisoquin is a substrate for cytochrome P450 enzymes, primarily CYP2D6.
• Genetic variations in CYP2D6 lead to significant inter-individual differences in drug metabolism.
• Understanding population-specific frequencies of metabolic phenotypes is crucial for personalized medicine.

Purpose of the Study:

• To investigate the prevalence of debrisoquin hydroxylation polymorphism in a healthy Turkish population.
• To determine the frequency of poor metabolizers (PMs) within this cohort.
• To compare the observed PM frequency with data from other Caucasian populations.

Main Methods:

• A cohort of 326 unrelated healthy Turkish volunteers was recruited.
• Debrisoquin sulfate (10 mg) was administered orally to all participants.
• Urinary debrisoquin and 4-hydroxydebrisoquin levels were quantified over an 8-hour period.
• The metabolic ratio (MR) of debrisoquin to 4-hydroxydebrisoquin was calculated to phenotype individuals.

Main Results:

• Debrisoquin oxidation exhibited a clear polymorphic pattern.
• Eleven subjects (3.37%) were phenotyped as poor metabolizers (95% CI: 1.69%–6.07%).
• Metabolic ratios ranged from 0.02 in extensive metabolizers to 263.8 in poor metabolizers.

Conclusions:

• The frequency of debrisoquin poor metabolizers in the Turkish population is comparable to that observed in other white populations.
• These findings contribute to the pharmacogenetic landscape of CYP2D6 in diverse ethnic groups.
• This data can inform drug dosing strategies and risk assessment for CYP2D6-metabolized medications in Turkish individuals.