Clinical Pharmacogenetics Implementation Consortium Guidelines for Cytochrome P450-2C19 (CYP2C19) Genotype and Clopidogrel Therapy

CYP2C19 is one of the principal enzymes involved in the bioactivation of the antiplatelet prodrug clopidogrel. A common loss-of-function allele, CYP2C19(star)2 (c. 681G>A; rs4244285), is associated with increased risk for serious adverse cardiovascular events in both heterozygous and homozygous patients (similar to 25-50% of the population) with acute coronary syndromes (ACSs) who are receiving clopidogrel, particularly among those undergoing percutaneous coronary intervention (PCI). We provide evidence from published literature and guidelines for CYPC19 genotype-directed antiplatelet therapy (periodically updated at http://www.pharmgkb.org).