Oxcarbazepine effectiveness as add-on therapy in Bulgarian patients with drug-resistant epilepsy

The study purpose was to perform an open, prospective study on various aspects of oxcarbazepine (OCBZ) effectiveness in Bulgarian patients with drug-resistant epilepsy. The study was performed with the participation of patients with epilepsy who attended the Clinic of Neurology at the University Hospital in Plovdiv, Bulgaria. Patients completed diaries about seizure frequency, severity, and adverse events. There were regular documented visits at 3 or 6 months during the first year of treatment with OCBZ and at 6 months afterwards, with dynamic assessment of seizure frequency, severity, adverse events, and EEG recordings. OCBZ was applied as add-on treatment in 82 patients (44 males, mean age 40 years). There was a relatively mild and stable dynamic improvement of seizure severity, a satisfactory seizure frequency reduction in 25.6% of participants, a stable mean seizure frequency reduction (40-38.55%) from the 6th to the 24th month of treatment and a stable responder rate (39-48.6%) during the same period. There were adverse events (generalized rash, dizziness, nausea, vomiting, edemas of the extremities, memory problems) in 8.54% of patients. In conclusion, OCBZ treatment is associated with: a low and stable improvement of seizure severity, a good and stable improvement of seizure frequency, a possible worsening of seizure control, a good safety and tolerability.