Gabapentin versus vigabatrin as first add-on for patients with partial seizures that failed to respond to monotherapy: A randomized, double-blind, dose titration study

Purpose: Our objective was to compare the efficacy and safety of gabapentin and vigabatrin as first-line addon treatment in patients with partial epil epsy. Methods: This was a multicenter, double-blind, randomized dose titration st udy. After baseline assessment and randomization, the dose could be increas ed if seizures persisted and reduced if side effects occurred. Health-relat ed quality of life was assessed at baseline and at the end of the study. By a protocol amendment post hoc, all randomized patients were offered a stan dardized perimetry examination at the end of the study. improvement rate wa s the proportion of patients with a reduction of seizure frequency of at le ast 50% during an 8-week period without any adverse events causing withdraw al. Results: One hundred two patients were randomized and analyzed on an intent -to-treat basis. The improvement rate was 48% in the gabapentin group and 5 6% in the vigabatrin group. The improvement rate, when per protocol criteri a were fulfilled, was 57% in the gabapentin group and 59% in the vigabatrin group. The proportion of seizure-free patients was 31% in the gabapentin g roup and 39% in the vigabatrin group. There was no difference in quality-of -life scores between the groups. Perimetry after termination of the study o n 64 patients showed abnormal results in 3 of 32 patients in the vigabatrin group. Conclusion: Approximately one third of the patients in both groups became s eizure-free. Although no major differences were seen in terms of the improv ement rate between the groups, equivalence between the two drugs was not fo und.