Abstracts

Oxcarbazepine (OXC) was approved in the United States in 2000 as adjunctive therapy for partial seizures in children ages 4 to 16 years and as monotherapy or adjunctive therapy for partial seizures in patients older than 16 years of age. This study serves to review the usefulness and tolerability of OXC in an academic referral center including the efficacy of this medication when used as monotherapy in our pediatric population, and also to decide if certain clinical factors contribute to treatment failure.
We retrospectively reviewed the records of 57 patients treated with OXC between January 2000 and April 2003. There were 23 children (age range, 2 -16) and 34 adults (age range, 17-82). OXC was used as either monotherapy or as add-on therapy. Parameters followed were efficacy (defined as a reduction in seizure frequency of at least 50%), length of treatment, side effects, and type of seizures. Initial dosing was as low as 10mg/kgm/day (approximately 75mg) in younger patients with titration to a maximum dose of 2400mg/day in older patients. We also reviewed the efficacy of OXC with regard to age, gender, MRI findings, EEG findings, and prior treatment failure.
The study included fifty-one patients with partial onset seizures, three with generalized seizures, and three with possible pseudoseizures. OXC was used as monotherapy in 30 patients and as add-on in 27 patients and showed overall effectiveness in 30/57 (52%). OXC showed effectiveness in 52.6% of adult patients, 76.5% when used as monotherapy and 35.3% when used as add-on therapy. When used in children, OXC was effective in 47.8%, 77% when used as monotherapy and 10% when used as add-on therapy. When we reviewed the cases with regard to contributing factors, we found that OXC was effective in 19/34 (56%) adults vs.11/23 (48%) children, 16/31 (52%) females vs. 14/26 (54%) males, 10/22 (46%) normal MRI vs. 11/20 (55%) abnormal MRI, 10/18 (56%) normal EEG vs. 20/27 (74%) abnormal EEG, 1/12 (8%) with intractable seizures vs. 29/45 (64%) without intractable seizures. Twenty patients (35%) experienced adverse events including sedation 9%, rash 7%, fatigue 7%, dizziness 5.3%, increased liver enzymes 1.7%, headache 1.7%, double vision 1.7%, and ataxia 1.7%. OXC was discontinued in 25 patients (43.9%), 11 (19%) related to adverse events and 14 (24.6%) related to lack of efficacy.
Our data confirms the initial studies of OXC in terms of efficacy and tolerability. It also indicates that OXC is useful as monotherapy for children with partial seizures. Factors we found contributing to lack of efficacy included prior treatment failure and having intractable seizures.