CYP2C19 is a drug-metabolizing enzyme associated with clopidogrel metabolism. CYP2C19 is known to produce genetic variations/mutations, which can affect the disposition of clopidogrel and therefore, the way people possessing the enzyme-mutations respond to the drug. CYP2C19 can be evaluated using either functional or genetic assays.
Certain common variants in the CYP2C19 gene are associated with decreased enzymatic activity and poor metabolism of clopidogrel, leading to a low level of active drug and potentially ineffective treatment for those possessing the variant. If CYP2C19 genotyping identifies one of these genetic variations, the physician may need to adjust the dosage of clopidogrel or prescribe an alternative therapy.
Although research has demonstrated that CYP2C19 variation contributes to a person's lack of responsiveness to clopidogrel, there is still a relatively small demand for testing at this point. This may change as algorithms are updated and if research studies prove the value-added benefit of these results.