In order to evaluate the effect of CYP3A5*3 allele on the pharmacokinetics of sildenafil, udenafil, and vardenafil, the clinical trial using a single oral dose was conducted in Korean healthy male subjects whose genotype of CYP3A5 had been determined.

The aim of this study is to evaluate the different effect of the CYP3A5 genotype on the pharmacokinetics(PK) of sildenafil, udenafil, and vardenafil in healthy male subjects. Twenty one healthy male subjects with CYP3A5*1/*1, *1/*3, or *3/*3 were enrolled. An open-label 3-way crossover study was performed with a week washout. A single oral dose of PDE5I (100 mg sildenafil; 200 mg udenafil; 20 mg vardenafil) was administered, respectively. After a single oral dose of phosphodiesterase type 5 inhibitor (PDE5I), plasma levels of the parent and the major metabolite were measured up to 24 or 48 h.

Inclusion Criteria:

• Healthy male subject whose CYP3A5 genotype was determined

Exclusion Criteria:

• Subject whose CYP3A5 genotype was not determined