Abstracts

Rationale: Lacosamide was licensed in Germany for the treatment of focal epilepsies in September 2008. The mechanism of action includes slow and sustained inactivation of sodium channels, different from the fast voltage-gated sodium channel inhibition that has been shown in antiepileptic drugs (AEDs) such as Carbamazepine (CBZ), Oxcarbazepine (OXC) or Lamotrigine (LTG). In addition, Lacosamide modulates the collapsin mediator response protein 2. Whether this effect contributes to its anticonvulsive effect has to be further evaluated. We describe efficacy and tolerability in 40 patients with focal epilepsies who received Lacosamide as adjunctive treatment for seizure control after launch in September 2008. Methods: 40 consecutive patients with focal epilepsies, (18 males and 22 females, age 18 - 71 years), who received Lacosamide as adjunctive treatment and have been followed-up for more than 3 months were included. The etiology and duration of epilepsy, number of previously and concomitantly used AEDs was documented. The daily dose of Lacosamide was stepwise uptitrated (50 - 100 mg per week) to a planned maximum dose of 400 mg/d (up to 600 mg/d in a few patients). Efficacy was calculated comparing the seizure frequency on Lacosamide treatment with the mean seizure frequency of the 3 months before starting Lacosamide. Efficacy was classified in four different groups: 1. no effect on seizure frequency, 2. < 50 % seizure reduction, 3. seizure reduction between 50 and 99 %; 4. seizure free patients. Assessment of tolerability was derived from patient reports of side effects and neurological investigations. Results: Efficacy (percentage of seizure reduction): group 1: 8 of 40 patients (20 %), group 2: 15 patients (37,5 %), group 3: 13 patients (32,5 %), group 4: 4 patients (10 %). Tolerability: most common side effects included dizziness (9 patients, 22,5 %), tiredness (3 patients, 7,5 %), nausea (2 patients, 5 %), double vision (2 patients) and unsteady gait (2 patients). Slower uptitration of Lacosamide (reducing the dose increment from 100 to 50 mg per week) and dose reductions of concomitant AEDs (especially CBZ, OXC, LTG) terminated side effects in most cases. In two patients a daily dose of 200 mg Lacosamide could not be achieved due to side effects, and Lacosamide treatment was terminated. In six other patients (15 %) Lacosamide was stopped due to lack of efficacy. Conclusions: Lacosamide is effective for adjunctive treatment of focal epilepsies. Lacosamide dosage up to 400 mg/d is well tolerated in most patients. To reduce the risk of side effects it may be advisable to reduce the speed of uptitration especially in patients using sodium channel blocking AEDs (CBZ, OXC, LTG) as baseline treatment.