In order to determine the efficiency of intranasal midazolam in prolonged convulsive episodes, we conducted a prospective study in children with various types of seizures. Nine patients (six buys, three girls; age range 6 months to 9 years) with prolonged convulsions lasting more than 10 min were treated with intranasal midazolam, 0.3 mg/kg. The success rate was 100% with only one case requiring a second dose. Estimated duration of seizures was 12-30 min (mean 18.6) while mean time elapsed until cessation of seizures was 139.6 s (range 60-480). No significant adverse effects were noted except fur one patient who had seizures secondary to serious CNS infection and respiratory depression after intranasal midazolam. (C) 2000 Elsevier Science B.V. All rights reserved.