Emerging antiepileptic drugs.

The introduction of several new antiepileptic drugs in the United States is likely in 1993. Many new drugs have undergone testing, but the four currently considered the most important are felbamate, gabapentin, lamotrigine, and vigabatrin. When these drugs are used as add-on therapy for patients with intractable epilepsy, 20 to 60% of patients show at least a 50% improvement in seizure frequency and 7% become seizure free. An overview of these agents is presented.