Seizure freedom with more than one antiepileptic drug.

Many people with epilepsy take antiepileptic drug (AED) polytherapy, although supportive evidence for the success of this strategy is sparse. Of 2881 treated patients registered in our database, 1617 (56%) have been seizure-free for at least the previous year, with 21% taking more than one AED (287 on two, 86%; 42 on three, 13%; 3 on four, 1%). There were 40 effective duotherapies and 28 triple therapies. Treatment with two or three but not four AEDs may be a useful therapeutic option for patients not responding to monotherapy. Further explorations of the best regimens for individual seizure types and epilepsy syndromes is required.