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.
Conclusion: Omeprazole affects itraconazole kinetics, leading to a reduction in bioavailability and Cmax. These two drugs should not be used together.