Efficacy and safety of zonisamide as the first additional treatment in Chinese patients with focal or secondary bilateral tonic-clonic seizures: An observational ,prospective study

Background: To evaluate the efficacy and safety of zonisamide (ZNS) as the first additional treatment for focal or secondarily bilateral tonic-clonic seizure (sBTCS). Methods: A total of 118 patients between 18 and 75 years of age with focal or sBTCS were recruited from multiple hospitals in Shandong province between May 13, 2021, and February 16, 2022. All received ZNS as the first additional treatment after clinical judgment. Seizure frequency, retention, and adverse events (AEs) were assessed 2 and 5 months after the introduction of ZNS. Results: Overall response rates at 2 and 5 months were 79.5% and 75.5%, respectively, whereas seizure-free rates at the same point were 53.6% and 51%, respectively. The review's retention rates at 2 and 5 months were 95% and 86%, respectively. The most common AEs were anorexia with weight loss (11.8%), dizziness (6.9%), and headache (3.9%). Conclusions: Our real-world study confirmed the efficacy and safety of ZNS as a first-additional treatment for focal or sBTCS in Chinese patients, with a high short-term retention rate.