Mexiletine: biphasic action on convulsive seizures in rodents.

Mexiletine, an antiarrhythmic drug, exerted a protective effect in mice against convulsive seizures induced by electroshock or the chemical convulsant, pentylenetetrazol, and against seizures induced in inbred audiosusceptible mice by a sound signal. Administered in large doses, mexiletine produced a hyperkinetic myoclonic syndrome of 30-60 min duration. The hyperkinesia could be controlled by dimethylaminoethanol, phenobarbital and by an experimental anticonvulsive agent, eboracin.