Effect of omeprazole on the pharmacokinetics of itraconazole.
OBJECTIVE
To investigate the effect of omeprazole on the pharmacokinetics of itraconazole.


METHODS
Eleven healthy volunteers received a single dose of oral itraconazole (200 mg) on days 1 and 15 and oral omeprazole (40 mg) once daily from day 2 to day 15. Itraconazole pharmacokinetics were studied on days 1 and 15.


RESULTS
Concentrations of itraconazole were higher when it was taken alone than when it was taken with omeprazole. With concomitant omeprazole treatment, the mean AUC0-24 and Cmax of itraconazole were significantly reduced by 64% and 66%, respectively.


CONCLUSIONS
Omeprazole affects itraconazole kinetics, leading to a reduction in bioavailability and Cmax. These two drugs should not be used together.
Jaruratanasirikul
S
S
Department of Medicine, Faculty of Medicine, Prince of Songkla University, Hat Yai, Thailand.
Sriwiriyajan
S
S
D000328:Adult; D000897:Anti-Ulcer Agents / Q000494:pharmacology*; D000935:Antifungal Agents / Q000097:blood / Q000493:pharmacokinetics*; D001682:Biological Availability; D004347:Drug Interactions; D005260:Female; D006801:Humans; D017964:Itraconazole / Q000097:blood / Q000493:pharmacokinetics*; D008297:Male; D009853:Omeprazole / Q000494:pharmacology*; D012016:Reference Values
D000897:Anti-Ulcer Agents; D000935:Antifungal Agents; D017964:Itraconazole; D009853:Omeprazole