Since many factors, both genetic and non-genetic factors, might influence pharmacokinetics of clopidogrel, the impact of following potential covariates was evaluated: age, weight, sex, diabetes mellitus, co-administration of PPI or statins, the presence of CYP2C19*2, CYP2C19*17, CYP3A4*1G alleles, and ABCB1 3435 TT genotype. This evidence concerns the gene CYP3A4 and diabetes mellitus.