Omeprazole drug interaction

Omeprazole Interactions:

• Cilostazol Omeprazole increases the exposure to cilostazol. Cilostazol dose reduction might be required.

• Clopidogrel Omeprazole might reduce the antiplatelet effects of clopidogrel. Consider giving an H2 receptor antagonist (not cimetidine) or pantoprazole instead.

• Clozapine Omeprazole possiblyreduces clozapine concentrations. Monitor for reduced clozapine efficacy.

• Methotrexate Reduced methotrexate elimination has been reported in patients given proton pump inhibitors with high-dose methotrexate. Routine methotrexate monitoring should detect any toxicity; some advise against concurrent use and suggest that omeprazole should be stopped five days before starting methotrexate.

• Phenytoin Phenytoin exposure might be increased or not affected by omeprazole. Any interaction seems unlikely to be clinically significant, but be alert for signs of phenytoin toxicity.

• Tacrolimus Omeprazole might affect tacrolimus exposure; consider monitoring tacrolimus concentrations when either drug is started or stopped.

• Voriconazole Voriconazole increases the exposure to omeprazole. Omeprazole might increase the exposure to voriconazole and serious neurological adverse effects have been seen in some patients. Voriconazole dose reduction is recommended.

Key points

• Omeprazole might increase exposure to citalopram but the clinical relevance is unclear. Patients should be alerted to the possibility of an increase in citalopram adverse effects.

• No additional precautions or dose adjustments appear to be necessary with the concurrent use of omeprazole and clarithromycin.

• Omeprazole reduces the exposure to itraconazole given as capsules, but not when given as itraconazole solution. Taking itraconazole capsules with an acidic drink, such as non-diet cola, can increase gastric acidity and therefore increase the absorption of the drug.