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Dose-response study of vigabatrin in children with refractory epilepsy
J L Herranz1, R Arteaga, I N Farr
1Neuropaediatric Service, Valdecilla Hospital, University of Cantabria, Santander, Spain.
Insights
Vigabatrin as add-on therapy effectively reduced seizures in children with severe refractory epilepsy. Many children experienced significant seizure reduction with good tolerability and no observed tolerance over time.
Area of Science:
- Pediatric Neurology
- Pharmacology
- Epilepsy Research
Background:
- Severe refractory epilepsy poses significant challenges in pediatric populations.
- Existing antiepileptic drugs often have limited efficacy in severe cases.
- Add-on therapy is a crucial strategy for managing difficult-to-treat epilepsy.
Purpose of the Study:
- To evaluate the dose-response relationship of vigabatrin as add-on therapy.
- To assess the efficacy and tolerability of vigabatrin in children with severe refractory epilepsy.
- To determine the long-term effects and safety profile of vigabatrin treatment.
Main Methods:
- A dose-response study involving 20 children (2 months to 18 years) with severe refractory epilepsy.
- Vigabatrin was administered as add-on therapy to existing antiepileptic drugs.
- Dose escalation and a 9-month follow-up phase were implemented to assess efficacy and tolerance.
Main Results:
- 15% of patients achieved seizure freedom, and 45% showed a 50-99% reduction in seizure frequency.
- During follow-up, 65% of patients reported a 50-99% seizure reduction, indicating sustained efficacy.
- Adverse effects (drowsiness, fatigue) were transient and mild in 15% of patients, with good overall tolerability.
Conclusions:
- Vigabatrin demonstrates significant efficacy as an add-on therapy for pediatric severe refractory epilepsy.
- The drug is well-tolerated, with transient side effects and no observed tolerance during long-term use.
- Vigabatrin represents a valuable therapeutic option for children with difficult-to-control seizures.
Abstract:
Twenty children aged 2 months to 18 years were included in a dose-response study of vigabatrin as add-on therapy to preexisting antiepileptic drugs (up to two per patient). All children had severe refractory epilepsy: partial seizures with or without secondary generalization in 19, and myoclonic seizures in one. After a 2-month observation period and a 1-month add-on placebo period, a fixed dose of add-on vigabatrin was given for 2 months: 1, 1.5, or 2 g/day, according to body weight (mean dose, 60 mg/kg/day). Three patients (15%) became seizure free, and nine (45%) showed a 50% to 99% reduction in seizure frequency. In the 17 patients whose seizures were not totally suppressed, vigabatrin dose was increased for a further 2 months, and in 7 patients who still showed less than 50% reduction in seizure frequency, vigabatrin dose was increased again. Efficacy appeared unchanged by these higher doses. During a 9-month follow-up phase, no tolerance to the effects of vigabatrin was observed, with three children seizure free and 13 (65%) reporting a 50% to 99% reduction in seizure frequency. During the study, adverse effects were recorded in three children (15%), namely drowsiness, constipation, fatigue, and apathy. These effects were generally transient, being observed during the dose-modification phase and disappearing either spontaneously or on reduction of vigabatrin dose. Clinical and laboratory tolerability to vigabatrin appeared to be very good, with no patients having withdrawn from the study because of side effects. A slight reduction in red blood cell count and hemoglobin levels was noted but was of doubtful clinical significance.(ABSTRACT TRUNCATED AT 250 WORDS)