Topiramate in the long-term management of refractory epilepsy

Purpose: A total of 292 adult patients (mean age, 33 years) with partial and/or generalized seizures previously resistant to antiepileptic drug (AED) therapy (median baseline seizure rate, 12 seizures/month) were treated with open-label topiramate (TPM) in dosages of 100-1,600 mg/day. Methods: The mean duration of TPM treatment was 413 days (range, 84-804 days), and the mean TPM dosage was 503 mg/day (range, 100-1,600 mg/day; median TPM dosage, 300 mg/day). Seizure reduction was calculated from seizure counts during the last 3 months and last 6 months of TPM therapy compared with baseline. Results: Overall, >50% of patients achieved greater than or equal to 50% seizure reduction. More important, 11% of patients were seizure-free for greater than or equal to 3 months at the last visit; 10% of patients were seizure free for greater than or equal to 6 months at the last visit. This robust therapeutic response was consistent for patients receiving TPM dosages >400 and <400 mg/day. The most commonly reported adverse events were related to the central nervous system. Over the 2.2-year treatment period, 19% of patients discontinued TPM therapy because of inadequate seizure control; 32% discontinued because of adverse events. Findings from this study show that TPM is a useful agent for long-term seizure control, with some patients becoming seizure free for extended periods despite failing previous AED therapy.