Abstracts

Rationale: Clobazam has only recently been approved in the United States by the FDA as an adjunctive therapy for the treatment of seizures associated with Lennox-Gastaut syndrome in patients 2 years of age and older. However, clobazam has been used in clinical practice as an adjunctive treatment for other epilepsy syndromes. The purpose of this study is to describe our experience with the efficacy and safety of clobazam in refractory epilepsy at a large pediatric center. Methods: We retrospectively reviewed all patients who were treated with clobazam as adjunctive therapy for refractory epilepsy between January 2001 and March 2013 and who had a follow-up visit at least one month after starting clobazam. Response to clobazam was defined as 50% reduction in seizure frequency at the time of last follow-up visit compared to baseline before starting clobazam. Results: Three-hundred-and-seventy-seven patients were prescribed clobazam, of which 205 (median age 8.5 years, interquartile range 4.2-11.6 years) had follow-up data 1 month after starting clobazam. Median follow up was 7 months (interquartile range 3-12 months). At the time of clobazam introduction, 23 (11.2%) patients were on one other antiepileptic drug (AED), 66 (32.2%) patients were on two AEDs and 99 (48.3%) patients were on 3 or more AEDs. Subsequently, 17 patients were on clobazam monotherapy. Response to treatment with clobazam was observed in 138/205 (67.3%) patients. Twenty-four (11.7%) patients had <50% reduction and 14 (7.1%) had no change of seizure frequency. Fifty-six (27.3%) patients became seizure free. The median (interquartile range) starting dose was 0.21 (0.14-0.32) mg/kg/day, increasing 2.5 (0.0-5.0) mg/week to a target dose of 0.47 (0.27-0.83) mg/kg/day after one week with a maximum titration period of 18 weeks. Forty-five (22%) patients discontinued clobazam, 12/205 (5.8%) due to adverse effects and 33 (16.1%) due to lack of efficacy. The most common adverse effects were drowsiness/tiredness (18.1%) and mood or behavioral changes (6.8%). Conclusions: Clobazam is a well tolerated antiepileptic drug, with overall good treatment response rates in pediatric patients with refractory epilepsy.