EFFECTS OF VIGABATRIN ON PARTIAL SEIZURES AND COGNITIVE FUNCTION

Forty five patients with refractory partial seizures were studied in a prospective, randomised, placebo controlled, add on, parallel group, double blind trial of the new antiepileptic drug vigabatrin (1.5 g twi ce daily) followed by open treatment. Seizure frequency was monitored throughout an eight week baseline, 20 weeks double blind, and up to 18 months of open vigabatrin treatment. Cognitive function, including me asures of memory and concentration, mood, and behaviour were assessed at baseline and again during the 20th week of treatment. Vigabatrin wa s associated with a significant reduction in a measure of motor speed and overall score on a design learning test in the first 20 weeks of t reatment. In comparison with the baseline period, vigabatrin treatment was associated with a significant reduction in median complex partial seizure frequency four to 12 and 12 to 20 weeks after commencing viga batrin (-66% and 69% in the vigabatrin group, + 50% and + 25% in the p lacebo group). Ten of 20 patients on vigabatrin and four of 23 on plac ebo showed a > 50% reduction in complex partial seizure frequency in t he last eight weeks of double blind treatment. At least 60% of respond ers had maintained the response to vigabatrin when assessed during the open phase of the trial at 44 weeks. Two patients discontinued vigaba trin because of depression, which resolved on drug withdrawal.