title: Stereospecific analysis of omeprazole supports artemisinin as a potent inducer of CYP2C19.
abstract: The purpose of the study was to determine the enantiomer pharmacokinetics of omeprazole and 5-hydroxy-omeprazole before and after administration of the antimalarial artemisinin to confirm artemisinin's ability to induce CYP2C19. Nine healthy male Vietnamese subjects were given a single 20 mg dose of omeprazole orally 1 week before (day - 7) artemisinin administration. Artemisinin was then given orally (500 mg) for 7 days (days 1-7). On days 1 and 7, a single 20 mg dose of omeprazole was coadministered with artemisinin. After a washout period of 6 days, a single 20 mg dose of omeprazole was again administered together with a single 500 mg of artemisinin (day 14). Stereoselective pharmacokinetics of omeprazole and 5-hydroxyomeprazole was determined on days of omeprazole administration. Seven days of artemisinin administration significantly decreased the AUC of both omeprazole enantiomers (day 7), compared with day 1 (P < 0.001). All values were normalized after the washout period. Artemisinin increased the AUC ratio of R-5-hydroxyomeprazole/R-omeprazole significantly (P < 0.01) on day 7. The AUC ratio of omeprazole sulphone/S-omeprazole did not differ between study days. Artemisinin decreased the AUC of S-omeprazole to the same extent as that of R-omeprazole in extensive CYP2C19 metabolizers. suggesting that artemisinin induces a different enzyme in addition to CYP2C19. These results support and strengthen earlier findings that artemisinin induces CYP2C19 as well as at least one enzyme other than CYP3A4.
authors.affiliation: Department of Medical Laboratory Sciences and Technology, Karolinska Institute, Huddinge University Hospital, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Mihara
authors.forename: U S
authors.initials: US
authors.lastname: Svensson
authors.forename: G
authors.initials: G
authors.lastname: Tybring
authors.forename: T N
authors.initials: TN
authors.lastname: Hai
authors.forename: L
authors.initials: L
authors.lastname: Bertilsson
authors.forename: M
authors.initials: M
authors.lastname: Ashton
mesh_terms: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000962:Antimalarials / Q000494:pharmacology*; D019540:Area Under Curve; D037621:Artemisinins; D001189:Aryl Hydrocarbon Hydroxylases; D002851:Chromatography, High Pressure Liquid; D065731:Cytochrome P-450 CYP2C19; D065607:Cytochrome P-450 Enzyme Inhibitors; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000097:blood / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors*; D009853:Omeprazole / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics*; D012717:Sesquiterpenes / Q000494:pharmacology*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
chemical_list: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000962:Antimalarials; D037621:Artemisinins; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; D012717:Sesquiterpenes; C049963:5-hydroxymethylomeprazole; C031327:artemisinin; D006899:Mixed Function Oxygenases; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; D065731:Cytochrome P-450 CYP2C19; D009853:Omeprazole