Add-on vigabatrin in children with refractory epilepsy - A 4-year follow-up study

Information on the long term efficacy and tolerability of vigabatrin in children is scarce. This open, 4-year add-on study reports the effects of vigabatrin in 22 children aged 26 to 220 months with refractory epilepsy. The 22 children entered this 4-year long term study after 2 months of add-on vigabatrin at a fixed dose, and two 2-month periods of vigabatrin adjustment. During those 4 years, 2 patients with complete response moved away, 3 with a seizure reduction of > 50% left the study at parental request, and 5 (23%) were withdrawn because of inefficacy or an increase in seizure frequency. Five patients (23%) reported adverse events such as drowsiness, fatigue, apathy, constipation and aggressiveness, although none resulted in vigabatrin withdrawal. In the 12 children completing the study, vigabatrin at a daily dose of 63.8 +/- 19.0 mg/kg reduced the median number of seizures from 30 seizures/month at baseline to 0 seizures/month at the end of the 4 years (p < 0.05) - a seizure reduction of > 50% in 9 of the 12 patients (complete control in 7 patients). It is concluded that add-on vigabatrin achieved a 4-year long term benefit in at least 40% of children with refractory partial epilepsy, and that the development of tolerance or adverse events were rarely observed in this period.