TUESDAY, June 29 (HealthDay News) -- The American College of Cardiology Foundation (ACCF) and the American Heart Association (AHA) released a joint clinical alert on June 28 to guide physicians in the interpretation of the boxed warning recently placed on the antiplatelet drug clopidogrel (Plavix) by the U.S. Food and Drug Administration. The full text of the alert will be co-published online June 28 in the Journal of the American College of Cardiology and Circulation.
David R. Holmes Jr., M.D., of the Mayo Clinic in Rochester, Minn., the chair of the committee responsible for the alert, and five colleagues wrote the alert, which stresses that no patient should stop taking clopidogrel without consultation with their physician. The authors write that between 2 and 14 percent of patients have a genetic variance which places them in a group of "poor metabolizers," making it more likely that the prescribed clopidogrel dose will be ineffective in platelet inhibition and in preventing potentially fatal cardiovascular events.
The clinical alert makes six recommendations to physicians caring for patients on clopidogrel. The authors write that for those on clopidogrel who have already had an adverse event while taking the drug correctly, using an alternative antiplatelet therapy or changing the dosing of clopidogrel is a reasonable option. They emphasize that adherence to evidence-based guidelines should be the foundation of care and the clinicians should be aware that genetic variability in response to the drug can affect its efficacy. Results of large clinical trials to assess the predictive value of pre-drug genetic testing and the use of individual genotyping in effectively using clopidogrel will be needed, the authors add.
"For some of the clinical issues in this document, final published data may not be available, in which case we have clearly identified this concern in the text. In addition to this document, an expert consensus document on the interaction of clopidogrel and proton pump inhibitors is in progress by the ACCF, American College of Gastroenterology, and AHA. Our organizations remain committed to providing guidance on key clinical issues to promote optimal patient care," the authors write.