We evaluated our clinical experience with
zonisamide, a broad-spectrum
antiepileptic drug, in a group of children with predominantly medically
refractory epilepsy. A retrospective chart review was conducted on patients at our tertiary referral center following Institutional Review Board approval. Observers documented reports of seizure frequency, and seizure types were identified either clinically or by prior video-electroencephalography monitoring. We identified 68 patients (age range 1.9-18.1 years [median 6.9 years]; male to female ratio 1.3:1) treated with
zonisamide for 0.7 to 28.9 months; at the last visit, 22% and 78% were on monotherapy and adjunctive
therapy, respectively. The median
duration of treatment and maintenance dose at the end of the follow-up were 11.2 months and 8.0 mg/kg/day, respectively. Seizure types included generalized (primary generalized tonic-clonic, myoclonic, tonic, atonic, absence) and partial (simple, complex, and secondarily
generalized tonic-clonic seizures); 10 (15%) patients had both partial and
generalized seizures. Sixteen (25.8%) patients were seizure free, although five of them were already in remission prior to starting
zonisamide. Thirteen (21.0%) patients had a > 50% seizure reduction, 10 (16.1%) patients had a < 50% seizure reduction, 14 (22.6%) had no improvement in baseline
seizures, and 9 (14.5%) reported having increased
seizures. The latter were mostly associated with dosage alterations in concomitant
antiepileptic drugs. Common side effects were central nervous system related, including behavioral or psychiatric (23.5%),
cognitive dysfunction (12.0%), and sedation (10.3%). Eleven (16.2%) patients ultimately discontinued
zonisamide, but only five were strictly due to side effects.
Zonisamide is clinically effective against multiple seizure types in a significant proportion of children with
epilepsy across a broad age range.
Drug discontinuation as a result of side effects is uncommon.