CYP2C19 Test for Clopidogrel (Plavix) Resistance

On March 12, 2010, the FDA announced
that they are adding a black box warning to the Plavix label to advise physicians of the importance of genetics and the availability of testing.

Click Here - Download an information package for your physician

Several recent landmark studies have proven the importance of 2C19 genotyping in treatment using clopidogrel or Plavix. Researchers have found that patients with variations in a gene called cytochrome P-450 2C19 (CYP2C19) have a 3.58 times greater risk for major adverse cardiovascular events such as death, heart attack, and stroke; the risk was greatest in CYP2C19 poor metabolizers. The abstract is available in the online verison of the New England Journal of Medicine.

Population Frequency of Cytochrome P450 (CYP) 2C19 Metabolizer Types

*There is wide variability among populations. People of Asian and African
ancestry have a a greatly increased prevalence of poor metabolizer status.

CYP2C19 is not just involved in the metabolism of clopidogrel, it metabolizes many other medications including antidepressants, barbituates, proton pump inhibitors, antimalarial and antitumor drugs.

Who Should Be Tested

The CYP2C19 test for clopidogrel or Plavix is considered appropriate for any patient taking or considering this medication.

Click here to view a list of drugs for which DNA testing may be helpful.

The Testing Process

The process is simple. You can order testing directly if you have a physician prescription or your healthcare provider can request testing for you. We send a cheek swab collection kit with directions by mail. Samples are submitted using the enclosed return mailer and results are provided in ten days or less. Faster testing is available for an additional charge. Call a DNA testing consultant at (800) 523-3080 for details and to order, or request information to you or to your healthcare provider on your behalf, simply complete the request form.

References

http://www.medscape.com/viewarticle/508543_2

Oesterheld, Jessica, M.D. GeneMedRx Drug Metabolism Tables

Simon et al. 2009. Genetic Determinants of Response to Clopidogrel and Cardiovascular Events. New Engl J Med 360(4):363-75.

Mega et al. 2009. Cytochrome P-450 Polymorphisms and Response to Clopidogrel. New Engl J Med 360(4):354-362.

Gladding et al. 2009. Pharmacogenetic Testing for Clopidogrel Using the Rapid INFINITI Analyzer: A Dose-Escalation Study. JACC 2(11):1095-1011.

Note: Testing requires a prescription from a physician.