A Discounted Interaction, Divalproex sodium and Topiramate Induced Hyperammonemic Encephalopathy – A Case Report

An interaction between divalproex sodium and topiramate may induce hyperammonemic encephalopathy, a well-documented, but seemingly overlooked or minimized adverse drug interaction. This case report highlights a 54 year old Caucasian female who presented with sedation, mental status changes, and a history of repeated hospitalizations of similar presentation along with hyperammonemia. The patient had a significant past medical history for seizure and psychiatric conditions. A serious drug-drug interaction between divalproex and topiramate was overlooked in this patient, potentially causing hyperammonemic encephalopathy. Clinicians must work to be vigilant in monitoring medication lists for drug interactions, especially when polypharmacy is involved, in treating multiple disease states, or if the patient has numerous consulting specialists.