[A retrospective analysis of using zonisamide and retention in monotherapy among patients with epilepsy in routine...

Zonisamide is one of the first antiepileptic drugs of new generation with a wide spectrum of action. It is successfully used in treatment of epilepsy for 30 years. The study aims at analyzing the results of the multicenter Russian trial on the efficacy and tolerability of zonisamide and retention in monotherapy.

The analysis included 92 patients with focal epilepsy, aged 18-78 years, from 20 epileptology centers in different regions of Russia. The patients were treated with zonisamide in initial and subsequent treatment.

The efficacy (the reduction of seizure frequency by >50%) was achieved in 81 (91%) out of 89 patients (95% CI 83.6-95.7%). Fifty-two patients received zonisamide for more than one year. The efficacy was achieved in 50 (96.2%) (95% CI 88.2-99.2%), including 39 (79.6%) patients with remission out of 49 patients with assessment of seizure free periods (95% CI was 66.8-89% for the frequency of remissions). The adverse effects were recorded in 27 (29.3%) patients. Seven (7.6%) patients were withdrawn due to these effects. The maximal duration of observation period was 50 month. Mean time of retention in treatment was 42.4 month (95% CI 38.7-46.2 month). The total frequency of retention in treatment was 82.1% (95% CI 73.1-91%) during the whole observation period.