Nov. 17 (HealthDay News) -- Combining the antacid Prilosec with the popular blood thinner Plavix (clopidogrel) can cut the effectiveness of Plavix by half, putting patients at risk for heart attack or stroke, U.S. health officials said Tuesday.
"These recommendations are based upon recently submitted studies by the manufacturer of clopidogrel [Sanofi-Aventis and Bristol-Myers Squibb]," Mary Ross Southworth, deputy director for safety with the U.S. Food and Drug Administration's Division of Cardiovascular and Renal Products, said during a morning press conference.
"The results of those studies are to avoid the combination of those two medications," she said, adding that the tandem should be avoided even if the two drugs are taken hours apart.
Combining the two drugs is common because Plavix can upset the stomach. The FDA said patients taking Plavix can take alternatives to Prilosec, such as Mylanta, Maalox, or Zantac, Southworth said.
Prilosec is in a class of drugs called proton-pump inhibitors (PPIs). Prilosec was singled out because it was the only PPI tested in studies submitted by the manufacturer of Plavix, Southworth said.
However, proton-pump inhibitors similar to Prilosec -- such as Aciphex, Nexium, Prevacid and Protonix -- should also be avoided when taking Plavix, Southworth said.
Other drugs that may also interact with Plavix, making it less effective include: cimetidine (Tagamet), fluconazole (Diflucan), ketoconazole (Nizoral), voriconazole (Vfend), etravirine, felbamate (Felbatol), fluoxetine (Prozac), fluvoxamine (Luvox), and ticlopidine (Ticlid), according to the FDA.
Results of a study presented Monday at the American Heart Association's annual meeting in Orlando, Fla., also found that people taking the acid reflux drugs Prilosec or Protonix in combination with blood thinners such as Plavix had a higher risk for death after angioplasty than people who didn't take the two popular antacids.
In January, Sanofi and Bristol-Myers updated Plavix's labeling to advise against using it in combination with certain heartburn drugs, the Associated Press reported.
On Tuesday, Sanofi spokeswoman Noelle Boyd said the company had bolstered that language labeling. "We've strengthened the label to say that these drugs should be avoided altogether, not just discouraged," she said.
SOURCES: Nov. 17, 2009, teleconference with Mary Ross Southworth, Pharm.D., deputy director for safety, Division of Cardiovascular and Renal Products, Center for Drug Evaluation and Research, U.S. Food and Drug Administration; Associated Press