Boxed Warning Added to Clopidogrel [PLAVIX] Label

Prescribing information for clopidogrel (Plavix) will now include a boxed warning that the drug can be less effective in poor metabolizers, the FDA indicated. The new warning suggests that many if not all patients on clopidogrel should undergo genetic testing to determine whether they have variants of the CYP2C19 gene associated with poor metabolism of the antiplatelet drug. Clopidogrel is actually a prodrug that requires metabolic activation by the CYP2C19 enzyme to become effective. Poor metabolizers get little or no benefit from the drug at standard doses, and therefore are at increased risk for thrombotic events and death, the FDA said. The drug's label has carried a similar warning since May 2009, but the FDA said today that "it was important to highlight this risk in a boxed warning" in light of a subsequent review of data. Seven different variants of the CYP2C19 gene are associated with poor metabolism of clopidogrel. According to the FDA, patients with two loss-of-function alleles, which do not have to be identical, will be poor metabolizers. The agency estimated that 2% to 14% of patients are poor metabolizers, with some racial-ethnic groups more likely to be affected than others. Whites have the lowest prevalence of poor metabolism and Asians have the highest. The boxed warning also includes this advice to healthcare providers: "Tests are available to identify a patient's CYP2C19 genotype and can be used as an aid in determining therapeutic strategy." A Cardiologist at Brigham and Women's Hospital and Harvard Medical School in Boston, claims the warning effectively means every patient on clopidogrel needs to be tested, although the new label does not say so directly. Some 25 million prescriptions for clopidogrel were written in 2008, according to Drugs.com. The FDA also recommended that physicians "consider alternative dosing" if patients are found to be poor metabolizers. The FDA urged patients currently taking clopidogrel not to stop the drug unless told to do so by their physician. Concerned patients should discuss the new information with their doctors before making any change. Please remember, as with all our articles we provide information, not medical advice. For any treatment of your own medical condition you must visit your local doctor, with or without our article[s]. These articles are not to be taken as individual medical advice.Please remember, as with all our articles we provide information, not medical advice. For any treatment of your own medical condition you must visit your local doctor, with or without our article[s]. These articles are not to be taken as individual medical advice. Deepen your understanding of "medical malpractice"... www.MedMalBook.com For more health info and links visit the author's web site www.hookman.com