Omeprazole Drug Interactions

by on December 14, 2011

Omeprazole can have adverse effects when taken in combination with other medications. For example, omeprazole can reduce the effectiveness of the other medicine, increase levels of the other drug in the body or itself be adversely affected by the second medication.

Omeprazole Reducing Effectiveness of Other Drugs

Omeprazole may reduce the body’s absorption of medications and supplements such as erlotinib, iron, ampicillin, digoxin and ketoconazole.

This potentially makes these drugs less effective and therefore, patients on these medications should discuss alternatives to omeprazole with their healthcare provider. Omeprazole may also decrease the effectiveness of clopidogrel (plavix). Although there is disagreement on how serious a drug interaction this actually is, patients should not combine the medications without consulting their doctor first.

Significant Omeprazole Drug Interactions

Taking omeprazole with certain other medications such as tacrolimus, warfarin, cilostazol, citalopram, diazepam (valium), escitalopram (lexapro) and methotrexate may increase the levels of these drugs in the body.

Drugs like rifampin and St. John’s Wort can decrease levels of omeprazole in the blood, rendering it less effective. When combined with certain diuretics including bumetanide, chlorothiazide, chlorthalidone, ethacrynic acid, furosemide, hydrochlorothiazide, metolazone and torsemide, omeprazole may cause hypomagnesemia.

Other Drugs That Can Potentially Interact With Omeprazole

There are several other drugs that may interact adversely with omeprazole. Voriconazole may double the amount of omeprazole in the patient’s blood, potentially leading to a variety of side effects. However, this is usually only a problem for patients taking a very high omeprazole dosage. Omeprazole in combination with certain HIV medications is an interesting case, as it can either decrease or increase the level of the medication in the blood depending on the type of HIV drug. Patients should therefore check with their healthcare provider what specific effects omeprazole may have on their particular HIV medication.

This is by no means a comprehensive list of omeprazole drug interactions. Patients should always consult their doctor on potential interactions with their current medications before starting omeprazole. The patient’s current prescription medicines should be taken into account along with over-the-counter medications, vitamins and nutritional and herbal supplements.