Nerispirdine, an acetylcholine release enhancer and a K+/Na+ use-dependent channel blocker, was in clinical development with sanofi-aventis for the treatment of multiple sclerosis. Nerispirdine is not proconvulsant. It can inhibit axonal K(+) channels and this mechanism may underlie the ability of the drug to enhance neuronal conduction. Nerispirdine can also inhibit neuronal Na(+) channels, a mechanism that may explain why nerispirdine lacks proconvulsant activity.