title: Dextromethorphan polymorphic hepatic oxidation (CYP2D6) in healthy black American adult subjects.
abstract: The objective of this study was to assign metabolizer phenotype to 107 healthy adult black Americans using dextromethorphan as the substrate probe. Eligible subjects were unrelated, healthy, nonsmoking, aged 18-50 years, and taking no medications. Fifteen milliliters of dextromethorphan syrup (85 mumol, 30 mg) was administered orally at bedtime, and 8-h overnight urine was collected. Dextromethorphan and dextrorphan urinary areas and molar ratios were determined using high-performance liquid chromatography with fluorescence detection. A molar metabolic ratio of < 0.3 was used to segregate poor metabolizers (PM) from extensive metabolizers (EM). Data were obtained in 99 subjects: 68 women, 31 men. (Five were lost to follow-up, three did not take the probe drug.) Six (6.1%) were PM (five women, one man), and 93 were EM. The prevalence of PM was 6.1% (95% confidence interval, 2.3-12.7%) in our sample. This compares to 5 to 10% reported in white unrelated subjects and 1.9% in 106 black children (64 healthy and 42 with cancer), and 0-8.6% in black African populations. The clinical implications of these findings warrant further investigation.
authors.affiliation: Department of Medicine, University of Missouri-Kansas City, School of Medicine 64108, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Marinac
authors.forename: J W
authors.initials: JW
authors.lastname: Foxworth
authors.forename: S K
authors.initials: SK
authors.lastname: Willsie
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D044383:Black People; D019389:Cytochrome P-450 CYP2D6; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D003915:Dextromethorphan / Q000493:pharmacokinetics* / Q000652:urine; D003917:Dextrorphan / Q000378:metabolism / Q000652:urine; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008099:Liver / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D001741:Black or African American
chemical_list: D003917:Dextrorphan; D003915:Dextromethorphan; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D019389:Cytochrome P-450 CYP2D6