Abstracts

Rationale: Patients with mental retardation and epilepsy can have both partial and generalized seizure types, and their epilepsy may be difficult to classify as partial or generalized. The epilepsy is often refractory in these patients and they may benefit from a broad spectrum antiepileptic medication such as levetiracetam. However, levetiracetam behavioral side effects seem more common in these patients. We studied the efficacy and tolerability of levetiracetam in the treatment of refractory epilepsy in patients with moderate to severe mental retardation and developmental disability (MR/DD) institutionalized at the Clover Bottom Developmental Center. Methods: We retrospectively reviewed records from all MR/DD patients treated with levetiracetam over the last 7 years since levetiracetam was first marketed. Patients were assessed at regular intervals in an epileptology clinic at the institution. We reviewed all evaluations through the last documented visit. We recorded seizure frequency pre and post treatment, levetiracetam dosing, and adverse effects Results: The patient population consisted of 36 patients (21 male, 15 female; mean age 42 ± 12 years). The main seizure type was generalized tonic-clonic in 19 patients, complex partial with or without secondary generalization in 13 patients, and tonic, atonic, myoclonic and atypical absence in the remaining four patients. Patients received levetiracetam for an average of 1018 ± 551days. Only 5 of the 36 patients had levetiracetam discontinued either for poor tolerability (two patients) or for inefficacy (three patients), with a retention rate of 86%. The levetiracetam dose ranged from 500mg to 4000mg per day with an average dose of 2072 ± 1115 mg per day. Patients took an average of 1.35 additional antiepileptic medications. 26 patients (72%) had a greater than 50% reduction in seizure frequency. The median reduction in seizure frequency was 90%. Among the non-responders, 6 had worsening, and two of these had greater than 50% increase in seizure frequency. Conclusions: Levetiracetam is both well tolerated and effective at reducing seizure burden in MR/DD patient. The risks of behavioral adverse effects and seizure worsening should not limit the use of levetiracetam as the benefit greatly outweighed the risks in this patient group.