Lamotrigine: how effective is it 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 Lamotrigine (LTG) 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. The 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 LTG and at 6 months afterwards, with dynamic assessment of seizure frequency, severity, adverse events, and EEG recordings. LTG was applied as add-on treatment in 73 patients (47 males, mean age 36 years). There was a relatively mild and stable dynamic improvement of seizure severity, a satisfactory seizure frequency reduction in 39.7% of participants, a stable mean seizure frequency reduction (43-59%) from the 6th to the 36th month of treatment and a stable responder rate (55.7-59.4%) during the same period. There were adverse events (dizziness/vertigo, generalized edema, irritability, aggressiveness, speech disturbances, visual hallucinations, sleepiness, insomnia, headache, diplopia, nystagmus, impaired balance, muscle cramps, gastrointestinal discomfort, generalized rash, fatigue, nausea) in 12.3% of patients. In conclusion, LTG 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.