Time-dependent changes in serum concentrations of acyclovir and its metabolite, 9-carboxymethoxymethylguanine, in a patient with suspected acyclovir encephalopathy

Valacyclovir, a prodrug of acyclovir, may cause adverse drug reactions, so called acyclovir encephalopathy. The encephalopathy not be explained simply by blood concentrations, because recent reports suggest the involvement 9-carboxymethoxymethylguanine (CMMG), major metabolite acyclovir. present study demonstrates changes in serum concentrations and CMMG patient with suspected A 63-year-old male was prescribed loxoprofen valacyclovir for herpes zoster. Seven days after start medication, he showed signs confusion. next morning, emergently transported to hospital stroke. There no stroke lesion but evidence acute kidney injury, given emergency dialysis. With daily hemodialysis sessions performed three days, decreased, his state consciousness improved accordingly.The CMMG, as well is efficiently removed symptoms decreased concentrations. Therefore, if other organic diseases can ruled out encephalopathy, it advisable introduce immediately.