Plavix Plus Heartburn Drugs May Hike ...(laboratory study last January and felt w...),Health

Both Plavix and most proton pump inhibitors (PPIs) are metabolized by the same enzyme in the liver, Juurlink said, so the combination can make Plavix less effective.

"The PPI drug blocks the conversion of clopidogrel to its active state, so it can't have the anticlotting activity it is supposed to," said Dr. Christopher Cannon, a cardiologist at Brigham and Women's Hospital in Boston. "You're taking Plavix, but it's not having the anticlotting activity it should."

Cannon is a member of a research group that has found that individual genetic makeup can reduce the effectiveness of Plavix in some people.

The U.S. Food and Drug Administration has taken notice of the potential dangers of the Plavix-PPI combination. The agency issued a notice Monday saying it would conduct studies "that will allow a better understanding and characterization of the effects of genetic factors and other drugs (especially the proton pump inhibitors) on the effectiveness of clopidogrel."

The FDA notice did not refer specifically to an increased risk of heart problems. It did say that "health care providers should re-evaluate the need for starting or continuing treatment with a PPI, including Prilosec OTC, in patients taking clopidogrel" and that "patients taking clopidogrel should consult with their health care provider if they are currently taking or considering taking a PPI, including Prilosec OTC" (the over-the-counter, or non-prescription form, of the drug).

Juurlink said "most doctors are unaware" of the potential dangers of the combination. But, he noted that the new study found no increased risk with the use of the PPI pantoprazole (Protonix), which works by a different molecular mechanism.

"For me, if patients need to be on a PPI, I would preferably give pantoprazole and avoid other acid-lowering drugs," he said.

Cannon said
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