A retrospective evaluation of retigabine in patients with cognitive impairment with highly drug-resistant epilepsy

Purpose: The purpose of this study was to evaluate retrospectively the efficacy and tolerability of retigabine (RTG) in residential patients of an epilepsy center. Method: We used an industry-independent noninterventional retrospective evaluation on the basis of paper and electronic records plus interrogation of the treating neurologists. All patients (N=20; 7 females; mean age: 31.8, range: 18-54 years) started on RTG between May 2011 and March 2012 were included. Evaluation was carried out after 6, 12, and 24 months. Changes in seizure frequency were measured as the number of seizures during three months on RTG compared with a three-month baseline period. The Clinical Global Impression scale was applied to include qualitative changes in seizure severity. All but one patient had symptomatic (structural; one patient: metabolic) or cryptogenic focal or multifocal epilepsy. All had grade III drug-resistant epilepsy and cognitive deficits of different degrees. Results: The retention rates were 60% after 6 months, 35% after 12 months, and 20% after 24 months. At 12 months, there were 2 responders (10%): one had a >90% seizure reduction and the other had a >50% seizure reduction. Another 5 patients were still on RTG because of minor improvements. The reasons for discontinuation in 13 patients were adverse effects (6), lack of effect (6), and both (1). Cognitive or emotional changes were the side effects that most frequently led to discontinuation. Beyond the 12-month evaluation, 3 patients were discontinued as a consequence of the FDA warning regarding retinal pigmentation and discoloration of skin and nails in patients exposed to RTG. One patient had a moderate blue-gray finger coloring. Ophthalmological changes were not discovered. Conclusion: Retigabine proved to be useful only for a small minority of patients in a sample of patients with particularly difficult-to-treat epilepsy. (C) 2015 Elsevier Inc. All rights reserved.