Vigabatrin in refractory childhood epilepsy. The Brazilian Multicenter Study

Children, 47, with various types of severe drug-resistant epilepsy were entered into a prospective, add-on, open trial with vigabatrin. Patients with West syndrome and idiopathic generalized epilepsies were excluded. Seven children had the drug withdrawn, five because of increase in seizure frequency and two because of adverse effects. Drug efficacy, measured according to seizure type, showed a 100% decrease in seizure frequency in 18.6% of partial seizures and 17.3% of the generalized seizures. There was a higher than 50% decrease in 39.5% of partial and 60.8% of generalized seizures, and less than 50% decrease or increase in seizure frequency in 41.8% and 21.8% of partial and generalized seizures, respectively. Vigabatrin mean dosage during phase 3 was 63.6 mg/kg per day (S.D. = 30.5), ranging from 19.3 to 110.5 mg/kg per day. Parametric statistical analysis (Student's t-test) of seizure frequency between phases 1 and 3 showed a significant decrease in seizure frequency for partial (P = 0.022), and generalized seizures (P < 0.0001). Drug-related adverse effects were observed in 18/47 cases (38.3%), consisting mainly of irritability, hyperactivity, dizziness, somnolence and gastrointestinal symptoms.