In the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition with Prasugrel–Thrombolysis in Myocardial Infarction (TRITON–TIMI) 38 and Study of Platelet Inhibition and Patient Outcomes (PLATO) randomized clinical trials, prasugrel and ticagrelor displayed superior efficacy compared to clopidogrel in acute coronary syndrome (ACS) patients in the absence of CYP2C19 genotyping; however, these agents were associated with increased bleeding risk (9, 10). Here, CYP2C19 is linked to acute coronary syndrome.