Clinical experience with adjunctive perampanel in adult patients with uncontrolled epilepsy: A UK and Ireland multicentre study

Purpose: To derive clinically useful information about the efficacy and tolerability of adjunctive treatment with perampanel for refractory epilepsy in an outpatient setting. Method: We pooled retrospective casenotes data of adult patients with refractory epilepsy prescribed perampanel from 18 hospitals throughout UK and Ireland. Results: Three hundred and ten patients were included (mean age 40.9 [SD = 12.0], 50% women, 27.7% with learning disability). The mean duration of epilepsy was 26.7 years (range 2–67 years, SD = 13.5) and 91.9% were taking two or more anti-epileptic drugs at the time of perampanel initiation. Mean retention was 6.9 months (range 1 day–22.3 months, SD = 4.5). The retention was 86% at 3 months, 71% at 6 months, 47.6% at 12 months and 27% at 18 months. At final follow-up a >50% reduction in seizure frequency was reached in 57.5% of tonic–clonic seizures, 57.4% of complex partial seizures and 43.8% of simple partial seizures. Eleven patients (3.5%) became seizure free. Two hundred and nine patients (67.4%) experienced adverse effects and of these 67% withdrew treatment due to their effects. The most common were sedation, behaviour/mood disturbance, dizziness, and unsteadiness. Conclusion: Perampanel appears a safe and effective antiepileptic drug when used as adjunctive therapy in patients with uncontrolled partial epilepsy (including those with learning disability), although few patients achieved complete seizure control. Long-term retention was slightly lower than reported rates for other anti-epileptic drugs, potentially due to the highly refractory population. Monitoring for adverse effects on energy levels, mood and behaviour is recommended