Treatment of infantile spasms with zonisamide

We determined the efficacy of and tolerability to zonisamide (ZNS) in newly diagnosed patients with infantile spasms. ZNS, 4-20 mg/kg per day, was int roduced as an add-on therapy or monotherapy in 27 children with infantile s pasms (cryptogenic, 2; symptomatic, 25). The dosage was initially 2-4 mg/kg per day, and then was increased by 2-5 mg/kg every 2-4 days until the seiz ures disappeared. Nine (33.3%) out of the 27 patients who were administered ZNS exhibited the disappearance of seizures. ZNS was effective in all the cryptogenic cases and seven (28.0%) of the symptomatic cases. The effective daily doses were 5-12.5 mg/kg (mean, 7.8 mg/kg), and the daily dosages wer e 40-100 mg (mean, 61.1 mg). The steady-state plasma ZNS concentrations wer e almost within the therapeutic range. The mean time interval between the s tart of ZNS therapy and the seizure disappearance was 5.0 days. Six (75.0%) of eight effective cases, the exception being one for whom EEG was not per formed after the therapy, showed the disappearance of hypsarrhythmia. The r ecurrence of seizures were observed in four of the nine cases. No adverse r eaction to ZNS was noted in any patient. In conclusion, ZNS treatment is co nsidered to be worthwhile trying, for early stage therapy for infantile spa sms. (C) 1999 Elsevier Science B.V. All rights reserved.