FDA Slaps Boxed Warning on Plavix

The FDA has slapped a boxed warning - its most severe - on the popular blood thinner Plavix. It warns that some patients may not effectively metabolize the drug (these patients are referred to as "poor metabolizers") and therefore may not receive its full benefits. The FDA estimates that between 2 and 14 percent of the population are poor metabolizers and that the rate varies based on racial background.

The warning also advises healthcare professionals to consider prescribing other anti-platelet medications to poor metabolizers or consider alternative dosing strategies. In addition, the warning alerts healthcare professionals that tests are available to identify poor metabolizers.

Plavix is prescribed to help reduce the risk of heart attacks, unstoppable angina, strokes and cardiovascular death in patients who have cardiovascular disease. The drug works by decreasing platelet activity, making them less likely to form blood clots. In order for the drug to work, a patient's liver must convert, or metabolize, the drug to its active form. Poor metabolizers do not effectively convert Plavix to its active form, making the drug less effective.

The FDA advises patients not to stop taking Plavix unless directed to do so. If you have any concerns about Plavix, or if you want to find out if you are a poor metabolizer, please speak to your healthcare professional.

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