An in vitro study demonstrated that the clearance of losartan was reduced significantly in human liver microsomes obtained from CYP2C9*3*3 and CYP2C9*2*2 homozygous individuals, and from CYP2C9*3*1 heterozygous individuals but not from CYP2C9*2*1 individuals. In this study, no clear conclusion could be made regarding the CYP2C9*2*3 genotype. In another study, no influence of the CYP2C9 polymorphism on the pharmacokinetics of losartan or E-3174 was found after a single oral dose of 50 mg losartan.