Study: Concerns on mixing Plavix, heartburn drugs

Researchers found that patients who were taking Plavix with popular prescription heartburn drugs, including AstraZeneca PLC's Nexium, were significantly more likely to be hospitalized for a heart attack, stroke, chest pain or a coronary artery bypass operation than those who took Plavix alone.

The study followed more than 14,000 patients from 2005 to 2006 in a database kept by pharmacy benefits manager Medco Health Solutions Inc.

Nexium and other proton pump inhibitors, like Wyeth's Protonix, are used to treat chronic heartburn, in which stomach acids come back up the esophagus, causing pain and inflammation. Doctors frequently prescribe these drugs to patients on Plavix because the blood thinner has been linked to a higher risk of ulcers.

Medco said 40 percent of patients in its study were taking the prescription heartburn medications. The company's chief medical officer, Robert Epstein, said that if over-the-counter medications like AstraZeneca's Prilosec were included, the percentage would likely be even higher.

Epstein said heartburn drugs could interfere with a liver enzyme needed to process Plavix, neutralizing its effects.

He stressed that patients should not stop taking Plavix or heartburn drugs, particularly if they have a history of stomach problems.

"But if you're a person who's otherwise healthy taking Plavix, you might want to consider calling your doctor and asking, 'Do I need really need this' or 'Do I need it every day?' " Epstein said in an interview. "There are ways to look at this question now that we wouldn't have thought about previously."

Bristol-Myers also urged patients to talk with their doctor before taking action and questioned Medco's approach.

"While we are still reviewing the data, in general, retrospective analyses--in contrast to randomized clinical trials--are more subject to confounding factors," said spokesman Ken Dominski.