title: Relationship of CYP2D6 genetic polymorphisms and the pharmacokinetics of tramadol in Chinese volunteers.
abstract: OBJECTIVE
  To investigate the relationship between CYP2D6 genetic polymorphisms and the pharmacokinetics of tramadol in Chinese volunteers.
  
  
  METHODS
  A gene chip was established for determining CYP2D6 genotype. Forty adult healthy Chinese subjects were categorized as: group 1, CYP2D6*1/*1; group 2, CYP2D6*2/*2; group 3, CYP2D6*2/*10; group 4, CYP2D6*10/*10. After oral administration of 100 mg tramadol, plasma and urine samples were collected over a 32-h period.
  
  
  RESULTS
  The main pharmacokinetic parameters of tramadol and its metabolite O-demethyltramadol (M(1)) in groups 1 and 2 were not significantly different. However, they were significantly different between groups 3 and 1, groups 4 and 1 and groups 4 and 3.
  
  
  CONCLUSIONS
  CYP2D6*2 does not alter the pharmacokinetics of tramadol, whereas CYP2D6*10 did with homozygotes showing a more pronounced reduction than heterozygotes. The 32-h metabolic ratio of tramadol to M(1) were (mean +/- SD) 2.05 +/- 1.01, 2.13 +/- 0.83, 4.24 +/- 2.75 and 6.85 +/- 2.78, respectively, in CYP2D6*1/*1, CYP2D6*2/*2, CYP2D6*2/*10 and CYP2D6*10/*10 subjects, respectively.
authors.affiliation: Department of Pharmacology, Tianjin Medical University, Tianjin, China.
authors.forename: Q
authors.initials: Q
authors.lastname: Li
authors.forename: R
authors.initials: R
authors.lastname: Wang
authors.forename: Y
authors.initials: Y
authors.lastname: Guo
authors.forename: S
authors.initials: S
authors.lastname: Wen
authors.forename: L
authors.initials: L
authors.lastname: Xu
authors.forename: S
authors.initials: S
authors.lastname: Wang
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000701:Analgesics, Opioid / Q000493:pharmacokinetics*; D002681:China; D019389:Cytochrome P-450 CYP2D6 / Q000235:genetics* / Q000378:metabolism; D005260:Female; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D020641:Polymorphism, Single Nucleotide; D014147:Tramadol / Q000031:analogs & derivatives / Q000493:pharmacokinetics*
chemical_list: D000701:Analgesics, Opioid; C080580:O-demethyltramadol; D014147:Tramadol; D019389:Cytochrome P-450 CYP2D6