PSYCHOTIC AND SEVERE BEHAVIORAL REACTIONS WITH VIGABATRIN - A REVIEW

Behavioural disturbances and psychotic reactions are commoner in patie nts with epilepsy than in the general population and may be precipitat ed by the majority of antiepileptic drugs, including the newer ones. T hese reactions may be more frequent in patients with complex partial s eizures, reflecting underlying temporal lobe pathology. A review of th e literature on vigabatrin found an incidence of severe abnormal behav iour in controlled trials in adults of 3.4%. In children open studies gave an incidence of around 6%. This may be related to dosage and spee d of introduction. Such reactions may be related to changes in seizure central, either unaccustomed good control (forced normalisation) or b reakdown in control, implying non-specific causative mechanisms. Alter natively, any relationship to control may be fortuitous and specific, unknown pharmacological mechanisms may be involved. Appropriate risk r eduction measures include slow introduction, limiting the dose to that required for seizure control, slow withdrawal and increased vigilance in those on polytherapy or with psychiatric histories. Such advice is pertinent to all antiepileptic medications. Additionally, vigabatrin is probably contraindicated in idiopathic generalised epilepsies. Beha vioural reactions are uncommon with vigabatrin, and have not been show n to be greater with it than with other antiepileptic agents. Therefor e, it maybe inappropriate to withhold the drug from those who may bene fit from it.