Cytochrome P450 2C19 polymorphism and antiplatelet therapy. Who should really be genotyped?

CYP2C19 is one of the principal enzymes involved in the metabolism of clopidogrel. The genes encoding CYP enzymes are polymorphic, with common alleles conferring reduced function. A loss-of-function allele, CYP2C19*2, is associated with an increased risk of major adverse cardiovascular events, particularly stent thrombosis, in patients with acute coronary syndromes who are receiving clopidogrel, especially among those undergoing percutaneous coronary intervention. Newer, more potent P2Y12 inhibitors like prasugrel and ticagrelor have been introduced recently in the daily clinical practice with better cardiovascular outcome in these patients. The purpose of this review article is to provide information regarding the clinical use of CYP2C19 genotyping in patients requiring antiplatelet therapy.