Plavix to endure more intense clinical trialing due to recent publications. Image Source: Pharmalux

The FDA has notified healthcare professionals that Bristol-Myers Squibb and Sanofi-Aventis, the makers of Plavix (clopidogrel), have agreed to conduct studies—that will allow a better understanding and characterization of the effects of genetic factors and other drugs, especially proton pump inhibitors (PPI), on the effectiveness of clopidogrel.

The agency said it is aware of clinical studies that clopidogrel is less effective in some patients than it is in others.

Differences in effectiveness may be due to genetic differences in the way the body metabolizes clopidogrel or interference from other drugs, according to the FDA. The studies should lead to a better understanding about how to optimize the use of clopidogrel.

The FDA said that it recognizes the importance of obtaining these data promptly, but acknowledges that it could take several months to complete the studies and analyze the results.

Until further information is available, the FDA recommends the following:

• Healthcare providers should continue to prescribe and patients should continue to take clopidogrel as directed, because clopidogrel has demonstrated benefits in preventing blood clots that could lead to a heart attack or stroke.
• Healthcare providers should re-evaluate the need for starting or continuing treatment with a PPI, including Prilosec OTC, in patients taking clopidogrel.