Abstracts

Rationale: Retigabine (RTG) is a new antiepileptic drug (AED) for add-on-treatment of partial epilepsies with and without secondary generalization in adults, which is available in Germany since May 2011. Its mechanism of action, the activation of voltage gated potassium channels, is unique among AEDs. The aim of this study was the evaluation of patients under treatment with RTG with regard to seizure control and side effects. Methods: 40 consecutive patients suffering from focal epilepsies who started add-on-therapy with RTG since May 2011 were analyzed. Patients suffering from a progressive disease or psychogenic seizures, taking part in another treatment study or undergoing epilepsy surgery or implantation of a vagal nerve stimulator during the treatment with RTG were not included. Demographic data, aetiology of epilepsy, treatment response, co-medication and side effects were recorded. Results: 23 men and 17 women of median age 36 years (range: 19-72) and a median duration of epilepsy of 27 years (range: 4-65) were included. Median seizure rate before treatment with RTG was 16 per month (range: 2-80), number of AEDs over lifetime was between 4 and 23. Titration was performed according to the product information up to an initial dose of 600mg/day. Median final dosage was 600mg/day (range: 200mg-1200mg). Main aetiologies: 45% cryptogenic, 17.5% focal cortical dysplasia, 10% complex cerebral malformation. 30% underwent unsuccessful epilepsy surgery or implantation of VNS before treatment with RTG. Responder rates: 15% of the patients were responders with a seizure reduction (SR) between 50% and 100%: 2.5% became seizure free. In 5% of the patients SR was between 75% and 99%, in 7.5% SR was between 50% and 74%. 85% showed a SR below 50%. In one patient (2.5%) seizure situation worsened. In one patient seizure frequency did not change but non-convulsive status epileptici, occurring each week until treatment with RTG was initiated, stopped. Main co-medication: oxcarbazepine, levetiracetam and lacosamide. Median number of AEDs in co-medication was 2 (range: 1-4). Side effects were seen in 40% of the patients. Main adverse reactions: dizziness and tiredness 17.5% each, 7.5% diplopia. Medication was tapered in 60% of the patients (in 30% due to lack of effect, in 12.5% due to side effects, in 17.5% due to lack of effect and side effects). Conclusions: Compared to pivotal trails responder rate in our patients is lower: 15.0% versus 28-56% (depending on the dosage). This may be due to our highly therapy resistant population. Main side effects and rate of tapering of RTG due to side effects seen in our patients are similar to those described in the other trials.