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Avoid dangerous combination: Blood thinner Plavix with some heartburn drugs

Consumer Reports News: November 17, 2009 04:18 PM

The Food and Drug Administration warned today that people who take the blood thinner clopidogrel (Plavix) should not take the heartburn drugs omeprazole (Prilosec, Prilosec OTC, and generics) and esomeprazole (Nexium) because two new studies confirm that the combination could have dangerous consequences. The studies show that omeprazole and esomeprazole—both members of a class of stomach acid-reducing drugs called proton pump inhibitors, or PPIs—can lower the effectiveness of Plavix , putting people at risk of heart attacks or strokes.

Plavix is given to people after a heart attack to help reduce the risk of blood clots that can trigger another attack. The drug can be hard on the stomach and cause gastrointestinal bleeding, so people are often prescribed a PPI treatment, which reduces the amount of acid in the stomach and lowers the risk of stomach bleeding. But previous studies suggested this drug combination may actually increase the risk of having another heart attack. The FDA’s warning is based on two new studies from the makers of Plavix that show that both omeprazole and esomeprazole reduce the drug’s effectiveness because they block an enzyme in the body called CYP 2C19.

The agency said it does not have enough information to draw a conclusion about whether any other PPIs can be safely used with Plavix, but studies into this issue are being conducted. However, a different type of acid-reducing drug called cimetidine (Tagamet, Tagamet HB, and generics) also inhibits the CYP 2C19 enzyme and should not be taken with Plavix.

Several other drugs also block CYP 2C19 and should be avoided. These include two antidepressants: fluoxetine (Prozac, Sarafem, and generic) and fluvoxamine; three anti-fungal drugs: fluconazole, ketoconazole, voriconazole; the blood thinner, ticlopidine; the epilepsy drug, felbamate; and the HIV drug, etravirine. The FDA advises that if you are experiencing heartburn or acid reflux while taking Plavix, you should try using antacids ( Maalox, Mylanta, Rolaids, Tums and generics) and most H2 blockers such as famotidine (Pepcid), nizatidine (Axid) and ranitidine (Zantac), but not cimetidine (Tagamet, Tagamet HB, and generics).

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. Read more about omeprazole and other proton pump inhibitors in our free Best Buy Drugs report.

Photo courtesy of Amanda M Hatfield


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