Effectiveness of zonisamide in childhood refractory epilepsy

Introduction Zonisamide (ZNS) is a new generation antiepileptic drug (AED) used in refractory epilepsy. This study assessed the effectiveness and reliability of ZNS in childhood refractory epilepsy. Method Sixty-eight epilepsy patients who were followed up in the paediatric neurology clinic, between 2013 and 2019, and in whom add-on therapy ZNS had been added as their seizures had continued despite multiple drugs being used, were included in this retrospective study. Their demographic findings, seizure aetiology, pre-treatment and post-treatment electroencephalography findings, treatment responses and any side effects of the drugs given were assessed in these patients. Results There were 46 (67.6%) patients in the refractory generalized epilepsy (RGE) group using multiple AEDs and 22 (32.35%) patients in the refractory focal epilepsy (RFE) group. Of these patients, 12 (17.65%) were being followed up for idiopathic epilepsy and 8 (11.76%) were being followed up for epilepsy of unknown aetiology. Twenty-two (32.36%) patients were followed up for structural abnormality, 8 patients (11.77%) were followed up for genetic disease, 4 patients (5.88%) were followed up for infectious sequel, 14 patients (20.59%) were followed up for metabolic reasons. In the RGE group, a more than 50% reduction was found in the seizures of 26 (56.5%) patients, while the seizures of 7 (15.2%) patients were found to have terminated completely. In the RFE group, a more than 50% reduction was found in the seizures of 19 (86.4%) patients, while the seizures of 2 (9.1%) patients were found to have terminated completely. The termination or a more than 50% reduction in seizures in 4 of the 6 patients followed up for a diagnosis of tuberous sclerosis complex (TSC) was significant. Conclusion ZNS is an effective and reliable option as an add-on therapy in paediatric refractory epilepsy, especially in focal epilepsy. It can also be considered for treatment in TSC patients.