Efficacy and tolerability of zonisamide in juvenile myoclonic epilepsy.

The recommended treatment for juvenile myoclonic epilepsy (JME) is valproate (VPA). Recently, topiramate and lamotrigine have also been shown to be effective. The objective of this study was to evaluate the efficacy and tolerability of zonisamide (ZNS) in the treatment of JME. We retrospectively analyzed the records of 15 patients (three M, 12 F, ages 11-20 years) diagnosed with JME at our institution during 2001-2003, and treated with ZNS. Generalized tonic-clonic (GTC), myoclonic and absence seizure response was assessed. The ZNS dose range was 200-500 mg/day (2.0-8.5 mg/kg/day). ZNS was started as the first drug, and as monotherapy, in 13 and was added to VPA in two patients. Follow-up range was 2-24 months (mean 12 months). Overall, 80% of patients on ZNS monotherapy showed good control (> or = 50% seizure reduction). Sixty-nine, 62 and 38% of patients were free of GTC, myoclonic, and absence seizures, respectively. Seizure control was achieved within four to eight weeks of attaining the maintenance dose. One patient on polytherapy had a 75% reduction in seizure frequency, whereas the other patient showed no response. There were no ZNS-VPA interactions. One patient stopped ZNS and was switched to VPA because of poor seizure control. Three patients (20%) experienced side effects (weight loss, headache, dizziness) during escalation, which resolved during maintenance. In this open-label, retrospective study, ZNS was shown to be an effective and well-tolerated drug in the treatment of patients with JME. The ease of titration, good safety profile, once-a-day dosing, lack of significant drug interaction, and short latency for onset of efficacy make ZNS an attractive therapeutic alternative for the treatment of JME.