Valacyclovir toxicity in peritoneal dialysis

Abstract

Valacyclovir (Prodrug) an antiviral agent is not well cleared by peritoneal dialysis and can cause neuropsychiatric manifestations in patient with renal failure on peritoneal dialysis and having Herpes Zoster infection being treated with this drug. Methodology followed for the collection of data and literature review was by using a medline search using the terms Acyclovir, nervous system effects, Valacyclovir, neurotoxicity and peritoneal dialysis. The representative case discussed is about an elderly gentleman with chronic renal failure on CCPD presenting with hallucinations, altered sensorium and restlessness following treatment with Valacyclovir 1000 mg three times per oral daily who was admitted and evaluated. It is of vital importance to consider the differential diagnosis of Herpes zoster encephalitis in the differential diagnosis of these patients as it is difficult to rule it out. The mechanism of this drug induced neurotoxicity is thought to be probably, the accumulation of serum carboxymethoxymethyl guanidine (CMMG), a toxic metabolite of valacyclovir.As peritoneal dialysis is not very effective in removal of this drug, it is thought to be beneficial to change to Hemodialysis for short duration so as to clear the drug from the system as shown in the case and in the discussion. Safe doses in peritoneal dialysis are not clearly delineated. Extreme precaution must be exercised while prescribing these group of anti-viral drugs in patients with CKD and especially those on peritoneal dialysis. If such a patient does manifest neuropsychiatric symptoms it is necessary to immediately stop the drug concerned. Methods to increase the excretion of the drug must be employed immediately or to remove it by intensification of PD or ideally to aggressively remove it by means of hemodialysis. Moreover there is a paucity of similar reports in the literature.