A new boxed warning has been added to the anti-blood clotting drug Plavix by the Food and Drug Administration, who says the medication doesn’t work well in people who have difficulty metabolizing the drug.
Plavix is used by patients with heart disease to help decrease risk of heart attack, stroke and death. It works on platelets–special blood cells that help blood clot to stop bleeding–by preventing blood clots from forming.
Plavix needs to be activated by the liver enzyme, CYP2C19. Patients that have reduced liver enzyme function can’t activate the drug making it less effective for them. They’re called “poor metabolizers” and this puts them at greater risk of heart attack, stroke and death.
“We want to highlight this warning to make sure health care professionals use the best information possible to treat their patients,” said Mary Ross Southworth, a clinical analyst in the Division of Cardiovascular and Renal Products in the FDA’s Center for Drug Evaluation and Research.
The Agency says there are tests available to evaluate CYP2C19 and determine if you are a “poor metabolizer.” They say patients should talk to their doctors to determine if they should stop taking the drug.
Last November the FDA issued a warning about using Plavix in conjunction with over the counter stomach acid reducer Prilosec and Prilosec OTC when new data found that taking the two together reducedPlavix’s anti-clotting effect by about half. .
Plavix is available only by prescription. It’s made by Bristol-Myer Squibb and Sanofi Aventis, who issued the following statement “The revisions to the prescribing information for Plavix reflect the companies’ ongoing research in collaboration with the FDA, which better defines the patient population that may be affected by a genetic variation in CYP2C19 and alternate treatment strategies.”
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