[Clinical analysis of the effectiveness and safety of vigabatrin]

The efficacy and safety of vigabatrin (VGB) has been extensively evaluated in preclinical and clinical studies but level of effectiveness in different type of seizures has yet to be established. The aim of our study is the prospective evaluation of anticonvulsant efficacy and toxicity of VGB. This long-term observation mainly focusing on efficacy of VGB in partial vs. secondarily generalized seizures were considered separately. In our study the criterion of drug resistance is occurrence per month of at least 1 tonic-clonic seizure or at least 2 complex partial seizures in 3 following months. The studies are based on 73 patients (39 F and 34 M), with average age of 26 years. After two weeks of treatment with sabril the drug was withdrawn in 5 patients because of side effects. The period of observation was 12 months. In group I--from total of 73 patients with partial seizures (including secondarily generalized)--31 (42%) of patients suffered only from partial seizures. Complex partial seizures occurred in 18 of patients; in this group were also 13 patients with simple partial seizures. Group II consisted of 42 patients (58%) who suffered from secondarily generalized tonic-clonic seizures. Number of seizures in group of patients with tonic-clonic seizures was from 1 to 16 per month (average 3.4) and in group of patients with complex partial seizures was from 1 to 70 per month (average 13.29). After titration period, Vigabatrin was given in doses of 500 to 3500 mg daily. Mean monthly fit frequency was calculated for over 3 months prior to the addition of vigabatrin and 12 months of therapy at the patient's maximum dose. Monthly fit frequency expressed as mean +/- standard error of the mean, and this statistical significance was determined using MANOVA for repeated measurement. Average monthly fit frequency of partial seizures has been reduced from 13.29 to 6.96 (p < 0.0001) and of generalized seizures from 3.38 to 1.38 (p < 0.0001). The percentage of patients achieving an increase of at least 75%--(Ratio < -0.6)--of seizures was greater in generalized seizures (27.3) than in partial ones (21.3). VGB is effective and well tolerated in refractory patients requiring add-on antiepileptic treatment and it has shown efficacy both in therapy of refractory partial seizures as well of secondarily generalized ones.