Drug Interaction Between Clopidogrel and Omeprazole
The U.S. Food and Drug Administration (FDA) has new data showing that omeprazole —a medicine used to reduce stomach acid—reduces the anti-blood clotting effect of clopidogrel by almost half when these two medicines are taken by the same patient. Patients at risk for heart attacks or strokes who use
clopidogrel to prevent blood clots will not get the full effect of this medicine if they are also taking omeprazole. This effect is called a drug interaction and it occurs because omeprazole blocks the conversion of clopidogrel into its active form.
Since clopidogrel can cause bleeding in the stomach, medications like omeprazole may be used in combination to reduce the production of stomach acid, and prevent stomach bleeding. Omeprazole is available by prescription and as an over-the-counter (OTC) medication to treat frequent heartburn
FDA wants to emphasize the following information for patients using clopidogrel:
Patients who use clopidogrel and need a medication to reduce stomach acid can use antacids and most acid reducers, such as ranitidine or famotidine because the FDA does not believe that these medicines will interfere with the anti-clotting activity of clopidogrel. However, cimetidine should not be used.
The manufacturers of clopidogrel have agreed to look at other possible drug interactions with clopidogrel. In the meantime, the clopidogrel label will be updated with new warnings on omeprazole and other drugs that could interact with clopidogrel in the same way. When more information becomes available, FDA will communicate any additional recommendations or conclusions on the use of clopidogrel.