Abstracts

Zonisamide is a broad spectrum antiepilepsy drug (AED) indicated for the adjunctive treatment of partial seizures in adults; however, several small, open-label studies have indicated that it may be safe and effective as monotherapy. The purpose of this study was to evaluate the safety and efficacy of zonisamide monotherapy in a pediatric and young adult population.
Charts were reviewed for pediatric and young adult patients receiving zonisamide monotherapy for epilepsy at the Blue Bird Circle Clinic for Pediatric Neurology at Texas Children[rsquo]s Hospital. Evaluation parameters included seizure and epilepsy classification, seizure recurrence based upon caregiver reports and seizure diaries, changes in weight, and adverse effects.
Thirty-four patients were included in this study, 18 male and 16 female. Seizure types included generalized (including absence, tonic-clonic, and myoclonic), complex partial, and complex partial with secondary generalization. Mean patient age was 10.0 years (range=8 months to 21.8 years). Zonisamide monotherapy was begun as initial therapy in 15 patients or following sub-optimal response to other AEDs in 19 patients, 7 of whom had been tried on 2 or more AEDs. Zonisamide was most often initiated at 100 mg once daily and titrated to either efficacy or tolerability over 5 weeks. Patients received a mean maintenance zonisamide dosage of 267.6 mg/day (range=100 to 500 mg/day) for a mean duration of 7.8 months (range=1 to 15.5 months). Efficacy data were available for 25 patients. Seven patients have experienced seizure freedom (from generalized, absence, and complex partial seizures) while on zonisamide monotherapy. One additional patient experienced seizure freedom before discontinuing for adverse effects. Fourteen patients reported good to excellent seizure control, 1 reported poor control, and 2 reported no change. Mean body weight was 27.8 kg (range=9.25 to 63 kg) before and 29.0 kg (range=10.1 to 61.6 kg) after initiating zonisamide treatment (n=16). No serious adverse effects, rash, or oligohidrosis occurred. Most commonly reported adverse effects included decreased appetite, sleeplessness, and irritability. Five patients discontinued due to adverse effects.
Zonisamide was safe and effective as monotherapy in the treatment of a variety of seizure types in this cohort. Sixty-five percent of patients had good to excellent seizure control, including 8 patients who became seizure free. Adverse effects were mild to moderate, and body weight was not significantly affected. Zonisamide with once-a-day dosing represents a safe, effective, and convenient monotherapy choice for seizure control.
[Supported by: Elan Pharmaceuticals, Inc. ]