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U.S. Department of Health and Human Services


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Follow-Up to the January 26, 2009, Early Communication about an Ongoing Safety Review of Clopidogrel Bisulfate (marketed as Plavix) and Omeprazole (marketed as Prilosec and Prilosec OTC)

[11/17/2009] – The U.S. Food and Drug Administration (FDA) is recommending that the co-administration of clopidogrel (Plavix), a drug used to prevent blood clot formation, and omeprazole (Prilosec/Prilosec OTC), a proton pump inhibitor (PPI) used to reduce stomach acid, be avoided because omeprazole reduces the effectiveness of clopidogrel. The new recommendations, updated from a January 2009 Early Communication, are based on study results from the manufacturers of clopidogrel.

Patients who are at risk for heart attacks or strokes may not get the full protective anti-clotting effect if they are using clopidogrel and omeprazole together.

The studies confirm that co-administration of omeprazole with clopidogrel results in decreased levels of clopidogrel's active metabolite (through inhibition of the CYP 2C19 enzyme, the enzyme that forms the active metabolite), reducing clopidogrel's anti-clotting effect.

Sanofi-Aventis and Bristol-Myers Squibb, the makers of Plavix (clopidogrel), are updating this drug's label with the details of the studies and are conducting follow-up studies to further explore drug interactions with clopidogrel.

FDA has provided more detailed information about this drug interaction in a Public Health Advisory and Information for Healthcare Professionals sheet.

Other stomach acid reducing drugs, such as Zantac (ranitidine), Pepcid (famotidine), Axid (nizatidine), or antacids, are not expected to interfere with the anti-clotting activity of clopidogrel because they do not inhibit CYP 2C19 activity. Tagamet and Tagamet HB (Cimetidine) does inhibit CYP 2C19 activity and should not be used. Ranitidine and famotidine are available by prescription and OTC and antacids are available OTC.

Until further information is available, FDA recommends the following:

  • Avoid using omeprazole and clopidogrel together and at any time of the day. Separating the dose of clopidogrel and omeprazole in time will not reduce this drug interaction.
  • Avoid using other potent CYP 2C19 inhibitors, including esomeprazole, with clopidogrel.
  • At this time, FDA does not have enough information about drug interactions between clopidogrel and PPIs other than omeprazole and esomeprazole to advise on their use together.
  • Patients who use clopidogrel and need a medication to reduce stomach acid can use antacids and most H2 blockers such as Zantac (ranitidine), Pepcid (famotidine), Axid (nizatidine), but not Tagamet and Tagamet HB (cimetidine).
  • Patients taking clopidogrel should consult with their healthcare provider if they are currently taking or considering taking omeprazole, including Prilosec OTC.



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