Valacyclovir是一種acyclovir的前驅藥物。已有相當多的文獻證明慢性腎衰竭病患使用acyclovir治療和神經毒性的發生有關。一般來說，對於肌酐酸清除率小於10 ml/min腎衰竭患者使用valacyclovir的建議劑量為每日500 mg。在此，本文報告2個腎衰竭末期病患，一是使用腹膜透析治療，另一位則是血液透析，皆因帶狀、 疹感染，服用已調整過劑量的valacyclovir且只使用2次，總共1g，依然產生神經毒性症狀的案例。藥師對於腎衰竭使用腹膜透析或血液透析治療的病患，應用acyclovir或valacyclovir時，在劑量調整上是非常重要的，且應注意其神經毒性症狀的發生。
 

Valacyclovir is a prodrug of acyclovir. Neurotoxicity associated with acyclovir therapy was well documented, especially for patients with chronic renal failure. The generally recommended dose of valacyclovir is 500 mg daily for end-stage renal disease (ESRD) patients with creatinine clearance < 10 ml/min. We report two cases of ESRD, one treated by continuous ambulatory peritoneal dialysis (CAPD) and another by hemodialysis, in which, the administration of valacyclovir for the treatment of herpes zoster infection, resulted in neurotoxicity—even though the doses have been adjusted according to their renal function, and two oral doses of valacyclovir with 1g only were administered. Pharmacists should be aware of the neurotoxic potential of acyclovir and valacyclovir, and of the importance of dosage adjustment in the ESRD patients on CAPD or hemodialysis.