New warning on mixing Plavix, stomach drugs

Heart attack patients taking the blood thinner clopidogrel (Plavix) received a strong warning today about also taking a stomach-soothing proton pump inhibitor drug, such as Nexium, Prevacid, or Prilosec, at the same time. This drug combination is routinely prescribed to patients after a heart attack to decrease the risk of stomach irritation and bleeding, but a new study suggests the stomach drugs can interfere with how Plavix works and may actually raise the risk of having another heart attack.

Plavix helps reduce the risk of blood clots that can lead to another heart attack. However, it can also be hard on the stomach and cause gastrointestinal bleeding, so patients are often prescribed proton pump inhibitors (PPIs) to help prevent this. But previous studies have suggested the PPIs reduce Plavix's protective effect. The new study, which appears in the March 4 issue of the Journal of the American Medical Association, adds to the body of evidence that shows patients taking these drugs together face an increased risk of heart attack and death.

In the study, researchers examined the records of 8,205 patients taking Plavix after suffering a heart attack or angina. More than 5,200 patients were also taking a PPI. Nearly 30% of the PPI group died or were rehospitalized for heart attack or angina, compared with 21% of the patients who did not take a PPI. Overall, patients taking a PPI had about a 25% increased risk of death or being rehospitalized.

In January a Canadian study found that patients taking Plavix and a PPI had a 40% increased risk of having a second heart attack than patients taking only Plavix. At the time, the FDA said the evidence was insufficient to pin the blame on PPIs because some studies suggested the drugs did not interfere with Plavix. The agency is currently working with the makers of Plavix, Sanofi-Aventis and Bristol-Myers Squibb, to better understand how PPIs interact with Plavix. It could take several months before those studies are finished.

In the meantime, here's what our medical consultants recommend: The overall incidence of gastrointestinal bleeding with Plavix is actually quite low. Only about 2% of patients will experience this side effect (the risk will be higher if you are also taking aspirin). To help prevent bleeding while taking Plavix, instead of taking a PPI, a better option is an older class of drugs called H2blockers, which includes nizatidine (Axid), famotidine (Pepcid), and  ranitidine (Zantac). You could also try an antacid. These drugs have not been associated with dampening the protective effects of Plavix. You should also talk to your doctor about having periodic blood counts or monitoring of your stools in order to detect gastrointestinal bleeding you may not be aware of (black, tarry stools can be a sign of this, for example).

—Steve Mitchell, associate editor, Best Buy Drugs

For more information about Plavix and other blood thinner drugs, such as aspirin, that are used to reduce the risk of heart attack and stroke, see our free Best Buy Drugs report on antiplatelets.