Vigabatrin vs. carbamazepine monotherapy in newly diagnosed focal epilepsy: a randomized response conditional cross-over study.

The clinical efficacy and safety of vigabatrin (VGB) as add-on therapy for pharmaco-resistant focal epilepsies is well established. However, for an objective evaluation, the effects of the drug in the monotherapy of newly diagnosed subjects should be determined. With this aim, VGB was compared, in a randomized, response conditional cross-over study, with carbamazepine (CBZ), the most widely prescribed drug in focal epilepsies. Fifty-one patients with complex partial (CP) seizures were randomly assigned to either the VGB or the CBZ group and evaluated after an initial 4 month period. The cross-over to the alternative drug was carried out, for an analogous period, only in cases with persisting seizures or in the presence of intolerable side effects. Patients who did not respond to either drug were subsequently treated with a combination of VGB and CBZ. No significant difference was revealed in the efficacies of VGB and CBZ; a complete control of seizures was obtained in 17/37 patients (45.9%) treated with VGB and in 20/39 patients (51.3%) treated with CBZ. The side effects were somewhat more frequent (41%) and severe with CBZ than with VGB (21.6%). The power to detect a 20% difference between the two drugs was 75%. The combination of the two drugs suppressed the seizures in 5 out of 14 resistant cases. The preliminary results in this small number of patients are encouraging and suggest that VGB may be considered as a first-line drug for epilepsy with CP seizures and as a valid alternative when other monotherapies are ineffective or poorly tolerated.