Abstract

TOLERANCE TO THE EFFECT OF NEWER-GENERATION ANTIEPILEPTIC DRUGS IN BULGARIAN PATIENTS WITH REFRACTORY EPILEPSY

Ekaterina Viteva* and Zahari Zahariev

Abstract

Objectives: To perform an open, prospective study on the tolerance to effect of newer-generation antiepileptic drugs (AEDs) as add-on therapy in Bulgarian patients with drug-resistant epilepsy. Methods: The study was performed with the participation of 1259 patients with epilepsy who attended the Clinic of Neurology at the University Hospital in Plovdiv, Bulgaria for regular visits and completed diaries about seizure frequency, severity, and adverse events. Results: Oxcarbazepine was used in 82 patients, topiramate - in 120 patients, lamotrigine – in 73 patients, levetiracetam – in 135 patients, pregabalin - in 47 patients, tiagabine – in 43 patients, gabapentin – in 18 patients, lacosamide – in 12 patients, retigabine – in 6 patients. Tolerance to effect of AED was confirmed in 47.06% on treatment with tiagabine, 33.87% of those on topiramate, 12.68% of those on levetiracetam, 39.02% of those on lamotrigine, 48.15% of those on oxcarbazepine, and 48% of those on pregabalin. The risk of tolerance development was much lower in patients on treatment with levetiracetam compared to other AEDs, and lower in patients on treatment with topiramate compared to those on oxcarbazepine. Conclusion: There is substantial risk of tolerance development in patients on treatment with most newer-generation AEDs, with the exception of levetiracetam.

Keywords: newer-generation; antiepileptic drugs; epilepsy; tolerance; effect.