EFFECTS OF DIFFERING DOSAGES OF VIGABATRIN (SABRIL) ON COGNITIVE-ABILITIES AND QUALITY-OF-LIFE IN EPILEPSY

Vigabatrin (VGB) prevents seizures by irreversible inhibition of gamma -aminobutyric acid (GABA) transaminase and a resulting increase in GAB A levels. We evaluated the cognitive and quality-of-life (QOL) effects of VGB in a double-blinded, add-on, placebo-controlled, parallel grou p dose-response study of patients with focal epilepsy whose complex pa rtial seizures (CPS) were difficult to control. In a single investigat ion, patients were randomly assigned to placebo (n = 40), 1 g VGB (n = 36), 3 g VGB (n = 38), or 6 g VGB (n = 32), treated for 12 weeks afte r a 6-week dose escalation period, and tested at the end of the baseli ne period and at the end of the treatment period with eight cognitive measures and three tests of mood and adjustment. The patient groups we re highly similar at study entry. Results at the end of the study show ed substantial relief from seizures. The Digit Cancellation Test showe d decreases in performance with increasing doses of VGB. Performance o n no other test showed any decrement with increasing dosage. Relief fr om seizures was not associated with changes on the psychological tests . VGB is a useful antiepileptic drug (AED) that has little impact on t ests of either cognitive abilities or QOL, even at a high dose.