A case of Neurotoxicity to Acyclovir has been reported in the American Journal of Case reports. Dr Seyed-Ali Sadjadi at Jerry L Pettis Veterans Memorial Medical Center, Loma Linda, USA and colleagues have reported the case.
Patients with a recent history of herpes zoster infection and underlying chronic kidney disease are the patient population most vulnerable to develop acyclovir-induced neurotoxicity. Renal impairment demands dosage adjustments of antiviral therapy to prevent potentially fatal drug toxicity. Use of acyclovir and its congeners, like, valacyclovir and ganciclovir, especially in patients with end-stage renal disease can be problematic due to their reduced ability to excrete the drug. These patients are prone to drug toxicity that can cause alteration of mental
status and encephalopathy.
An 80-year-old African American man with a history of arterial hypertension, congestive heart failure and end-stage renal disease, on cyclic peritoneal dialysis since 2012, developed pain, and swelling of the left side of his face, involving his left cheek and eye. The pain was radiating down to his jaw, feeling weak and febrile at times. He was seen in the emergency department where he was diagnosed to have developed herpes zoster. He was admitted to the hospital and per ID recommendations, and because of suspicion of encephalitis and
possible eye involvement, he was isolated and started on acyclovir at a dose of 5 mg per kg per day intravenously (IV), following drug manufacturer’s guidelines and continued on peritoneal dialysis per his usual prescription.
Shortly after taking the medication, he developed confusion, disorientation, and visual hallucinations. He was switched from PD to hemodialysis (HD), with successful recovery. Examination of the cerebrospinal fluid for meningitis and imaging studies of the head was negative. Serum levels of acyclovir were found to be elevated.
Even when the acyclovir dose is properly adjusted for kidney function based on the current manufacturer’s recommendations, it can cause neurotoxicity. Acyclovir has a high potential for nephrotoxicity and neurotoxicity
in patients with reduced kidney function; therefore, dose modification based on kidney function is mandatory, particularly in oliguric and dialysis-dependent patients.
Carry home Point-
In order to avoid neurotoxicity, we recommend an intravenous dose of 2.5 mg rather than the currently recommended dose of 5 mg/kg/day in ESRD patients. In the case of neurotoxicity, hemodialysis provides much faster removal of the drug than peritoneal dialysis.
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