Retrospective analysis of the efficacy and tolerability of levetiracetam in patients with metastatic brain tumors.

Seizures are a common complication of metastatic brain tumors (MBT), affecting approximately 27-50% of all patients during the course of their illness. Treatment of tumor-induced seizures is often inadequate with traditional antiepileptic drugs (AED) due to a variety of factors, including activation of glutamatergic NMDA receptors, alterations of neuronal input pathways, and tumor growth. Levetiracetam (LEV) is a 2nd generation non-enzyme inducing AED with a novel mechanism of action, binding to neuronal synaptic vesicle protein SV2A, that has been previously shown to reduce seizure activity in patients with primary brain tumors. Due to its unique mechanism of action, it has been postulated that LEV may also be effective in controlling seizures from MBT. A retrospective chart review was performed of all Neuro-Oncology Center patients with MBT who had received LEV for seizure control. Thirteen patients were reviewed with a median age of 55.1 years (range: 34-70). Six patients had breast cancer, five had lung cancer, and two had melanoma. LEV was used as an add-on AED in seven patients (54%) and as monotherapy in six patients (46%), with a median dose of 1,000 mg/day (range: 500-3,000). The baseline median seizure frequency was one ictal event every other day. After the addition of LEV, the median seizure frequency was reduced to 0 per week. The seizure frequency was reduced to less than 50% of the pre-LEV baseline in 100% of patients (P=0.0002, Sign test), with 10 patients (77%; confidence interval: 46-95%) noting complete seizure control. The most common adverse event was somnolence and headache, noted in 3 of 13 patients (23%). LEV was very effective and well tolerated in MBT patients with seizures and should be considered for add-on therapy or as a substitute AED for monotherapy.