Abstracts

Felbamate is a recent anti-convulsant medication that has been relegated to second-line therapy due to fear of side effects such as bone marrow or liver failure. These side effects are rare, uncommon, and almost unheard of in children under 13 years of age. Despite this fact, many children who could benefit from this medication have not been given a trial because of the fear of dangerous side effects. We conducted a retrospective review to analyze how effective felbamate was in a refractive epileptic population, and noted whether there were any abnormal blood or liver tests during treatment., A retrospective chart review of seizure patients treated with felbamate from 1994-2006 was performed. The average duration of therapy, prior failed treatments, laboratory values, and seizure type were reviewed. Average felbamate dose per day was calculated and average therapeutic serum levels were recorded. Patients were evaluated for seizure improvement as becoming seizure free, improvement of greater than 50%, improvement of less than 50%, and worsening of seizures. Reasons for stopping therapy were also recorded along with any perceived side effects., There were 28 patients (18 male, 10 female); average age 7.54 years (range 1.33-17.25 years). Average prior failed treatments was 3.6 drugs (range 1-6) or therapies (3 ACTH or 3 prednisone;6 ketogenic diet; 1 vagal nerve stimulator). The average duration of therapy was 23.6 months (range 2-93 months). Average maximum daily dosage was 1157mg/day, which was 50.1mg/kg/day (avg. weight 23.1Kg). The average trough serum level for our population was 55mg/dl (range 9-140mg/dl). Seizure types seen in patients were: myoclonic/drop seizures 12; atypical absence seizures 2, Landau-Kleffner 1; secondary generalized or mixed seizures 13. There were 7 patients that met criteria for Lennox-Gastaut Syndrome. Outcome for seizure control showed seizure freedom for 5 patients; greater than 50% improvement in 14; less than 50% improvement in 3; and worsened seizures in drop attacks or startles in 4. One patient stopped the medication despite better seizure control because of irritability. Before 1997, four patients stopped treatment from fear of side effects despite good seizure control. Two patients stopped for anorexia, but none stopped for insomnia which was treated by moving doses earlier in the day or lowering the dosage. There were no significant changes in weight, hematology, or liver profiles in any patient during treatment., This retrospective review of felbamate add-on therapy shows 22/28 pediatric patients with refractive seizures having improved seizure frequency. Only 4/28 patients worsened. The main reason for stopping therapy was the fear of side effects more than actual clinical side effects. This suggests that for intractable seizure patients, especially with mixed or myoclonic seizure types, felbamate should be a rational treatment choice despite known risks of toxicity.,