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Efficacy and Safety of Adjunctive Zonisamide in Adult Patients with Refractory Partial-Onset Epilepsy

A Randomized, Double-Blind, Placebo-Controlled Trial

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Abstract

Background and Objective: Clinical studies have reported that zonisamide is effective for a wide range of seizure types, including refractory partial-onset seizures. However, there have been no reported studies of the efficacy of zonisamide in the Chinese population to date. The aim of the present study was to evaluate the efficacy and safety of zonisamide in the treatment of adult Chinese patients with refractory partial-onset epilepsy.

Methods: This was a randomized, double-blind, placebo-controlled trial conducted over a 16-week period. 104 patients with refractory partial-onset epilepsy were enrolled. Participants were randomly assigned to receive addon zonisamide or placebo. Zonisamide was titrated to a target dosage of 300 or 400 mg/day. Seizure frequency and adverse effects were documented.

Results: 102 patients completed the trial. Zonisamide showed significantly greater efficacy compared with placebo (responder rate 55.8% vs 36.0%, p < 0.05), including 55.2% (16 of 29 patients) in the zonisamide 300 mg/day arm and 56.5% (13 of 23 patients) in the zonisamide 400 mg/day arm. Zonisamide 300 and 400 mg/day showed similar efficacy (p > 0.05). Moreover, similar efficacy of zonisamide was found in the control of complex partial seizures, simple partial seizures and secondary generalized seizures. There was no difference in the incidence of adverse effects between zonisamide and placebo. Reported adverse effects in the zonisamide group involved the digestive system (32.5% of total adverse effects in the group) [including transient increases in liver enzymes (27.8%)], weight changes (30.2%), the haematological system (15.1%), neurological/psychiatric effects (10.3%), the urinary system (7.9%) and the cardiovascular system (4.0%). Only digestive system adverse effects constituted a significantly higher proportion of adverse effects in the zonisamide group than in the placebo group (32.5% vs 30.2%, p < 0.05).

Conclusion: Zonisamide 300–400 mg/day is effective and well tolerated as an adjunctive drug in adult Chinese patients with refractory partial-onset epilepsy.

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Acknowledgements

No sources of funding were used to assist in the conduct of this study or the preparation of this article. The authors have no conflicts of interest that are directly relevant to the content of this study. Drs Yang Lu and Zhanqin Xiao contributed to this work equally.

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Correspondence to Xuefeng Wang.

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Lu, Y., Xiao, Z., Yu, W. et al. Efficacy and Safety of Adjunctive Zonisamide in Adult Patients with Refractory Partial-Onset Epilepsy. Clin. Drug Investig. 31, 221–229 (2011). https://doi.org/10.2165/11539750-000000000-00000

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  • DOI: https://doi.org/10.2165/11539750-000000000-00000

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