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U.S. Department of Health and Human Services


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Public Health Advisory: Updated Safety Information about a drug interaction between Clopidogrel Bisulfate (marketed as Plavix) and Omeprazole (marketed as Prilosec and Prilosec OTC)


The U.S. Food and Drug Administration (FDA) has new data showing that omeprazole (Prilosec/Prilosec OTC)—a medicine used to reduce stomach acid—reduces the anti-blood clotting effect of clopidogrel (Plavix) 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 using clopidogrel should consult with their healthcare provider if they are currently taking or considering taking omeprazole, including Prilosec OTC.
  • Both clopidogrel and omeprazole can provide significant benefits to patients, and patients should always consult with their healthcare professional before starting or stopping any medication.
  • It is very important that patients talk with their healthcare professional about any over-the-counter (OTC) drugs they are taking before starting or while using clopidogrel

Patients who use clopidogrel and need a medication to reduce stomach acid can use antacids (such as Maalox or Mylanta) and most acid reducers, such as Zantac (ranitidine), Pepcid (famotidine), or Axid (nizatidine) because the FDA does not believe that these medicines will interfere with the anti-clotting activity of clopidogrel. However, Tagamet and Tagamet HB (cimetidine) should not be used. Ranitidine and famotidine are available by prescription and OTC and antacids are available OTC.

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.


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