In all 3 studies, reduced-function allele carriers experienced significantly higher rates of cardiovascular death, myocardial infarction, and stroke.17–19 Considering the totality of evidence, the US Food and Drug Administration—approved clopidogrel label was updated to include a “boxed warning” to underscore that individuals carrying 2 reduced-function CYP2C19 alleles—so-called “poor metabolizers”—experience diminished effectiveness of the drug at standard dosing and that alternative therapeutic strategies should be considered in these patients. This evidence concerns the gene CYP2C19 and myocardial infarction.