Zurich Consensus Conference on New Antiepileptic Drugs. Introduction: goals.

Epilepsy is characterized by recurrent seizures. Many epilepsies with focal seizures as well as convulsive generalized seizures respond satisfactorily to antiepileptic drugs (AEDs) that reduce repetitive firing (e.g., phenytoin, carbamazepine, and valproate) or that augment GABAA-mediated inhibition (e.g., phenobarbital and benzodiazepines). A number of drugs presently under development, such as NMDA receptor antagonists, loreclezole, losigamone, methysticine, and dextromethorphan, are promising in acute animal models of otherwise drug-resistant convulsant activity. As a result of recent studies in both experimental models and surgically resected human epileptic brain, the prospects for development of AEDs have significantly improved. Several new AEDs recently have reached the commercial market or are in experimental or clinical trials. A comparative presentation of the standing of the new AEDs with respect to their efficacy and side effects is necessary, but still very difficult. Because initial experience with new AEDs is restricted to populations with severe drug-resistant epilepsy, the crucial question whether potential new AEDs can alter prognosis is not yet definitively answered. There is a clear need to compare the effects of standard AEDs and new AEDs in naive patients and over longer follow-up periods. Moreover, because of the strong desire to develop antiepileptic therapy that directly treats the primary etiology of a given epileptic syndrome, or modifies the neurobiological processes that cause recurrent seizures, better experimental epilepsy models for chronic epilepsy and further clinical studies are necessary to increase the knowledge on the pathophysiology of distinct epileptic syndromes. In this respect, studies on the differences between responders and nonresponders to a given AED treatment are extremely valuable.