Global distribution of CYP2C19 variants in clopidogrel-indicated populations: implications for pharmacogenomic-guided antiplatelet therapy

Clopidogrel is a widely prescribed antiplatelet prodrug, with activation affected by CYP2C19 loss- and gain-of-function variants. Whilst global CYP2C19 variant prevalence is well described, this scoping review characterises CYP2C19 diplotype and metaboliser phenotype frequencies in clopidogrel-indicated populations. A literature search of Scopus, PubMed, Ovid MEDLINE, and Ovid Embase was conducted from inception to 6 July 2026. Forty-one studies (n = 18958) reporting CYP2C19 diplotypes were synthesised across Asia, the Middle East and North Africa (MENA), Europe and the Americas and converted to phenotypes. Intermediate and poor metabolisers were most prevalent in East Asia (54.0–77.2%) and South Asia (47.3–71.1%). Rapid and ultrarapid metabolisers were most prevalent in MENA (27.3–44.3%) and Europe (27.3–36.2%). Frequent diplotypes were *1/*2 in intermediate and *2/*2 in poor metabolisers. Overall, phenotype distribution reflects global population trends. High global prevalence of CYP2C19 intermediate and poor metabolisers amongst clopidogrel-indicated populations presents an opportunity to implement pharmacogenomic-guided prescribing.