Vigabatrin in the management of generalized seizures in children

The interpretation of the results of the use of vigabatrin (VGB) in generalized seizures and epilepsies in children has been difficult. Most studies have assessed patients on the basis of both seizure type and epilepsy syndrome and the numbers of patients have been small. Some 'generalized' epilepsy syndromes (specifically the Lennox-Gastaut syndrome) are characterized by multiple seizure types which are frequently not analysed individually in terms of drug response. By contrast West syndrome is easier to evaluate as the spasms are the only, and characteristic, seizure type. Vigabatrin has been used as both add-on, and monotherapy in the treatment of spasms. The results of add-on studies suggest that symptomatic spasms respond best, with 40-100% of children becoming spasm-free and many others showing a reduction in seizures of over 50%. The limited, reported data on VGB-monotherapy in West syndrome have been encouraging with over 50% of patients experiencing a total and sustained control of seizures with minimal or no adverse events; however, the pattern of response (symptomatic cases responding better than cryptogenic cases), has not, as yet, been confirmed. The 'non-progressive' myoclonic epilepsies tend to be exacerbated with 25-50% of patients experiencing an increase in seizure frequency; this is an interesting observation in view of the improvement seen in infantile spasms, which are also classified as a myoclonic seizure. The use of VGB in other generalized seizures and epilepsy syndromes has been neither assessed, nor reported. This reflects the fact that these seizures/syndromes are easily and well controlled using the 'older' anti-epileptic drugs.