Abstracts

Rationale: Absence seizures may be refractory to traditional treatments (valproic acid, lamotrigine, ethosuximde) in a small number of children. Amantadine has previously demonstrated efficacy in small series against intractable absence and myoclonic type seizures (Shields, et al 1985). We sought to examine the efficacy of amantadine for treatment of refractory absence seizures in a cohort of pediatric patients.Methods: We reviewed all patients with absence seizures at Cook Children s Medical Center in which amantadine was initiated as treatment since 2007 and included those with >3months follow-up. Demographic data including gender, age at initiation, and epilepsy syndrome were abstracted, along with concominant AEDs, amantadine dosing (mg/kg) and seizure frequency at initiation. Outcome was determined at 3, 6, and 12 months post-treatment initiation categorized as >90% reduction, >50% reduction, or < 50% reduction in seizure frequency. Patients without adequate data to determine seizure reduction at each follow-up visit were excluded.Results: Thirteen patients were treated with amantadine, 2 discontinued within 1 month for lack of efficacy leaving 11 (8F:3M; mean age 9.4y, range 3.5-15.5y) in the final cohort, . No patient discontinued amantadine because of side effects. Seven (64%) had followup > 6months and 6 (55%) > 12 months. Patients had been exposed to an average of 3.4 AEDs (range 1-6) prior to initiation and 3 were implanted with VNS. Concominant AEDs and VNS settings were stable or reduced in all but 1 (9%) patient. The average starting dose of amantadine was 4.6mg/kg/d (2-7.4mg/kg/d). At 3 months (n=10), >50% seizure reduction was reported in 90% (>90% reduction in 60%) and 1 (10%) had <50% reduction. At 6 months (n=6), 3 had >90% seizure reduction and and 3 (50%) had <50% reduction. At 12 months (n=5), all had > 50% reduction with 4 reporting > 90% reduction. Patients that continued amantadine > 12months were on 0.8 concominant AEDs, a 55% reduction from baseline.Conclusions: A majority of patients experience >50% seizure reduction at 3, 6, and 12 months after initiation of amantadine for intractable absence seizures. A significant proportion of patients experienced > 90% reduction in seizure frequency and reduced concominant AED use by >50% at 12 months. Amantadine appears to be an efficacious alternative treatment for refractory absence and warrants further investigation.