Abstracts

Rationale: To assess the clinical experience with eslicarbazepine acetate (ESL), with focus on efficacy and tolerability in up to 3 years of treatment. Methods: Retrospective clinical data from patients in Norway, 2010-2014 were used and evaluated anonymously. The study was approved by the Regional Ethics Committee. Results: 104 difficult-to-treat patients were included (68/36 women/men, average age 41 years). 96 patients used 1-3 other antiepileptic drugs , 8 used monotherapy. 43 patients switched from oxcarbazepine to ESL and 12 from carbamazepine. Improved seizure control was obtained in 61 patients: 5 became seizure free, 24 had a substantial reduction in seizures and 32 had some improvement in seizure control . 43 had an uncertain effect. 69 (66%) of the patients still use ESL The drug was withdrawn in 35 patients, in 26 due to lack of effect, in 9 due to adverse effects. 81 patients were included >1 year before evaluation. 1 year retention rate amongst these was 64%. 23 out of 35 patients followed > three years still use ESL . The mean daily dose was 917 mg (range 400-1600 mg) and serum concentration 57 mmol/L (range 23-103). Adverse effects were reported in 47 patients (45%): Hyponatremia, cognitive impairment, sedation, headache, dizziness, nausea, skin reactions. Sodium levels were 120-144 mmol/L, 22 patients <137 mmol/L (21%), 25 had hyponatremia prior to ESL, 5 (4.8%) had hyponatremia with ESL, which is considerably higher than suggested in the product information of ESL (0.1-1%). Conclusions: The present study demonstrated a one-year retention rate of 64 %, improved seizure control after the introduction of ESL in 59% of difficult-to-treat patients. 45 % of the patients experienced adverse effects. Due to the risk of hyponatremia, serum sodium should be monitored carefully.