Clinical applications and the effect of mexiletine on refractory epilepsies

Twenty-four patients with refractory epilepsy were treated with mexiletine as an additional antiepileptic drug. As the initial responses, seizures were decreased by 50% or more in 7 (46.7%) of 15 patients with symptomatic partial epilepsy (SPE), in none of 7 with symptomatic generalized epilepsy (SGE), and in 1 of 2 with undetermined epilepsy. Seizures increased in 3 patients (20.0%) with SPE, and in 3 (42.9%) with SGE. Concerning seizure types, mexiletine had significant effects on 1 of 2 patients with simple partial seizures, on 7 of 13 with complex partial seizures, on 1 of 5 with secondarily generalized seizures, and on 1 of 8 with tonic seizures. No patients with a myoclonic seizure or atypical absence improved. Exacerbation of the seizures was observed in 2 of 13 patients with complex partial seizures, in 1 of 5 with secondarily generalized seizures, in 3 of 8 with tonic seizures, and in 2 of 3 with myoclonic seizures. Partial seizures were controlled well, whereas generalized seizures sometimes worsened. EEG improved in 3 patients with SPE; decrease of focal spikes in 2 patients and disappearance of secondary generalization in 1. Follow-up for more than 3 months showed seizures to be lessened in 2 patients. Mexiletine is useful for the treatment of refractory epilepsies, especially SPE.