FDA says Prilosec can block benefits of Plavix

WASHINGTON -- Federal health officials said Tuesday a popular heartburn medication can interfere with the blood thinner Plavix, a drug taken by millions of Americans to reduce risks of heart attack and stroke.

The Food and Drug Administration said the stomach-soothing drug Prilosec cuts the blood-thinning effect of Plavix by half.

Regulators said the key ingredient in Procter & Gamble's Prilosec blocks Plavix, known generically as clopidogrel, from taking full effect.

"Patients at risk for heart attacks or strokes who use clopidogrel to prevent blood clots will not get the full effect of this medicine," the agency said in a statement.

Plavix is marketed by Sanofi-Aventis and Bristol-Myers Squibb. With global sales of $8.6 billion last year, it's the world's second-best selling drug behind Pfizer's cholesterol drug Lipitor.

Because Plavix can upset the stomach, it is often prescribed with stomach acid-blocking drugs.

The FDA says patients who need to reduce their acid should take alternative drugs like Johnson & Johnson's Mylanta or Boehringer Ingelheim's Zantac.

Information about the drug interaction between Plavix and certain heartburn medications is not new. In January, Sanofi and Bristol-Myers updated Plavix's labeling to advise against using it in combination with certain heartburn drugs, following medical journal articles about the negative interaction.

A Sanofi spokeswoman said the company has now bolstered that labeling.

"We've strengthened the label to say that these drugs should be avoided altogether, not just discouraged," said Noelle Boyd, Sanofi's senior communications director.