Post-Marketing Clinical Study of Valaciclovir Hydrochloride Tablets -Single Oral Dose Study in Hemodialysis Patients-

Valaciclovir (VACV), the L-valyl ester prodrug of aciclovir (ACV), is extensively converted to ACV and L-valine after oral administration. In subjects with normal renal function, ACV is predominantly eliminated unchanged in the urine, with a small proportion metabolized to 9-carboxymethoxymethylguanine (CMMG). The metabolism of ACV to CMMG is thought to involve aldehyde dehydrogenase (ALDH). On the basis of a high proportion of the Japanese population having low-activity ALDH, it can be hypothesized that the conversion of ACV to CMMG is decreased, thereby leading, in patients with renal impairment, to higher plasma concentrations of ACV. This pilot study was conducted to investigate potential relationships between genetic polymorphisms of ALDH2, an isozyme of ALDH, and the plasma pharmacokinetics (PK) of VACV, ACV and CMMG in subjects with end-stage renal disease on hemodialysis.