Abstracts

Zonisamide (Zonegran[reg]) is a broad-spectrum antiepilepsy drug that is approved for partial seizures in adults and has been used in Japan since 1989 in both adults and children. Here we report 2 pediatric patients with intractable seizures who became seizure free upon addition of zonisamide to their therapeutic regimens.
The clinic records of 2 patients were reviewed for diagnosis, history, treatment outcome, and any adverse events.
Patient 1 (male) suffered a brain injury secondary to bacterial meningitis at 3.5 weeks of age. He has a history of infantile spasms and intractable mixed seizure disorder and carries a diagnosis of Lennox-Gastaut syndrome. At age 5 years he was having 15 to 25 myoclonic seizures per day in addition to other seizure types, which were refractory to lamotrigine and divalproex. Treatment with adrenocorticotropic hormone, phenobarbital, carbamazepine, topiramate, and the ketogenic diet had already failed. Zonisamide was initiated at 100 mg/day and titrated to 300 mg/day (20.7 mg/kg/day). Divalproex was weaned. All seizure types ceased entirely in July 2001, and Patient 1 continues to be seizure free on lamotrigine and zonisamide. No adverse events were reported. Patient 2 (male) has Lennox-Gastaut syndrome. At 4 years of age he was having 8 to 10 seizures each day, including staring spells and atonic seizures, while taking phenytoin and gabapentin. He had previously been treated, unsuccessfully, with carbamazepine, divalproex, lamotrigine, topiramate, and the ketogenic diet. Zonisamide was added to his regimen, and seizure frequency improved immediately. Zonisamide was titrated to 300 mg/day (17.6 mg/kg/day). In approximately 1 month, the patient was seizure free, and developmental progression was noted. He remains seizure free since November 2001 on the combination of phenytoin, gabapentin, and zonisamide. Gabapentin was successfully tapered in February 2002; however, the parents requested that it be restarted for behavioral management. The only adverse event reported was increased phenytoin level, which was corrected by adjusting the dosage of phenytoin.
Two pediatric patients with refractory epilepsy became seizure free upon the addition of zonisamide to their therapeutic regimens. Both patients remain seizure free without any serious adverse events. Although further study is warranted, the experience of these 2 patients suggests that zonisamide may be an appropriate choice for pediatric patients with myoclonic or atonic seizures.
[Supported by: Elan Pharmaceuticals, Inc.]