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Concentrations of Tramadol and O ‐desmethyltramadol Enantiomers in Different CYP2D6 Genotypes
Author(s) -
Stamer U M,
Musshoff F,
Kobilay M,
Madea B,
Hoeft A,
Stuber F
Publication year - 2007
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/sj.clpt.6100152
Subject(s) - tramadol , cyp2d6 , pharmacology , chemistry , enantiomer , urine , genotype , medicine , analgesic , biochemistry , stereochemistry , gene
The influence of CYP2D6 genotype and CYP2D6 inhibitors on enantiomeric plasma levels of tramadol and O ‐desmethyltramadol as well as response to tramadol was investigated. One hundred and seventy‐four patients received one hundred intravenous tramadol 3 mg/kg for postoperative analgesia. Blood samples drawn 30, 90, and 180 min after administration were analyzed for plasma concentrations of the enantiomers (+)‐, (−)tramadol and (+)‐, (−) O ‐desmethyltramadol by liquid chromatography‐tandem mass spectrometry. Different CYP2D6 genotypes displaying zero (poor metabolizer (PM)), one (heterozygous individual (HZ)/intermediate metabolizer (IM)), two extensive metabolizer (EM), and three (ultra rapid metabolizer (UM)) active genes were compared. Concentrations of O ‐desmethyltramadol differed in the four genotype groups. Median (1/3 quartile) area under the concentration–time curves for (+) O ‐desmethyltramadol were 0 (0/11.4), 38.6 (15.9/75.3), 66.5 (17.1/118.4), and 149.7 (35.4/235.4) ng·h/ml for PMs, HZ/IMs, EMs, and UMs ( P <0.001). Comedication with CYP2D6 inhibitors decreased (+) O ‐desmethyltramadol concentrations ( P <0.01). In PMs, non‐response rates to tramadol treatment increased fourfold compared with the other genotypes ( P <0.001). In conclusion, CYP2D6 genotype determined concentrations of O ‐desmethyltramadol enantiomers and influenced efficacy of tramadol treatment. Clinical Pharmacology & Therapeutics (2007) 82 , 41–47. doi: 10.1038/sj.clpt.6100152 ; published online 14 March 2007