[Acyclovir encephalopathy in a peritoneal dialysis patient despite adjusting the dose of oral acyclovir: a case report].

We report a case of acyclovir encephalopathy in a 77-year-old man who was introduced to peritoneal dialysis three years earlier. He developed herpes zoster and was treated with acyclovir (ACV) at 800 mg daily per oral. Two days later, he developed consciousness disturbance, hallucinations and asterixis. Acyclovir was stopped and continuous ambulatory peritoneal dialysis (CAPD) was switched to hemodialysis, which resulted in the resolution of his symptoms. Because the optimal dose of ACV varies among individuals depending on the bioavailability of ACV and metabolic enzyme activity, ACV encephalopathy can occur even when the acyclovir dose is modified according to the renal function of the affected patient. Because CAPD provides a poorer ACV clearance than hemodialysis, CAPD patients tend to have a higher risk of developing ACV encephalopathy and to recover more slowly. If CAPD patients develop ACV encephalopathy, a temporary change in the type of dialysis to hemodialysis should be considered.