Antiepileptic drugs in development.

BACKGROUND: Despite the success of several new antiepileptic drugs, about one third of patients with epilepsy are not seizure free on medication. Improvement in this situation might lie in drugs that are currently in development. RECENT DEVELOPMENTS: Some new antiepileptic drugs are modifications of those already available, referred to in this Rapid Review as evolutionary drugs. These modifications of existing drugs are developed to improve effectiveness, often by increasing tolerability. Other drugs work by new mechanisms and are usually discovered through screening of animal models. WHERE NEXT? The large number of drugs currently in clinical trials provides a measure of hope for patients whose epilepsy is not controlled with currently available medication. In the future, this range of antiepileptic drugs will probably increase because of the use of new animal models, discovery of new basic mechanisms of epileptogenesis, acceleration of proof of principle studies in people, and development of new methods of drug delivery.