Pharmacogenetics of Clopidogrel (Plavix)*New - Video from Duke on the recent GIFT study confirming the importance of CYP2C19 genetics 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 Several recent landmark studies have proven the importance of 2C19 genotyping in treatment using clopidogrel or Plavix. Researchers have found that patients with variants in cytochrome P-450 2C19 (CYP2C19) have lower levels of the active metabolite of clopidogrel, less inhibition of platelets, and 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
|
| Poor (no or low enzyme levels) |
Intermediate (reduced enzyme levels) | Extensive (normal enzyme levels) | |
| CYP2C19 | 3-21% | 24-36% |
43-73% |
*There is wide variability among populations. People of Asian and African
ancestry have a a greatly increased prevalence of poor metabolizer status.
CYP2C19 is an important drug-metabolizing enzyme that catalyzes the biotransformation of many other clinically useful drugs 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.
The Testing Process
The process is simple. We send a buccal or blood collection kit in the mail, and you return samples to our laboratory by overnight courier. Results are typically available within 10 business days. Accelerated (STAT) five-day testing is also available. Call (800) 523-3080 for more information or to obtain collection kits, or visit how to order for test requisition forms and sample requirements.
Included with each Genelex CYP2C19 test is 90-days access to GeneMedRx drug and gene interaction software so healthcare providers can see the effect of the genotype on all patient medications, herbals, and over-the counter medicines.
The program can also predict drug-drug interactions.
See a short video on Cardiosource Video Network about Clopidogrel, 2C19 Variants and Outcomes
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.
Disclaimer: The content on this page is intended for healthcare professionals.
The text presented on this page is not a substitute for professional medical advice. It is for your information only.
Unless provided information expressly states that is was created by an MD or PharmD or cites another specific source, it was authored by Genelex employees that are not healthcare providers.
