Valproate-induced hyperammonemic encephalopathy enhanced by topiramate and phenobarbitone: A case report and an update

Valproate-induced hyperammonemic encephalopathy enhanced by topiramate and phenobarbitone: A case report and an update

Blog Article

Although Bumper D-Ring sodium valproate (VPA)-induced hepatic encephalopathy is a well-recognized entity, VPA can occasionally produce encephalopathy secondary to hyperammonemia in the presence of normal hepatic function, namely valproate-induced non-hepatic hyperammonemic encephalopathy (VNHE).Known risk factors include therapy with multiple antiepileptic drugs, especially when topiramate is one of the drugs; presence of underlying inborn errors of metabolism; febrile states; and insufficient nutritional intake.We describe a 5-year-old male child who developed VNHE while on polypharmacy with topiramate and phenobarbitone; the child also had poor nutritional intake.The encephalopathy reversed with withdrawal of VPA and treatment with L-carnitine.We emphasize the need for early recognition, investigation, and treatment of this potentially life-threatening condition.

We also recommend that VPA, topiramate, Capris and phenobarbitone should not be given in combination.