The Efficacy And Safety Of Zonisamide As An Adjunctivetreatment For People With Drug-Resistant Partial Epilepsy:a Meta Analysis

BackgroundThe majority of people with epilepsy have a good prognosis and their seizures can be well controlled with the use of a single antiepileptic agent, but up to30%develop drug-resistant epilepsy, especially those with partial seizures. In this review we summarize the current evidence regarding zonisamide, when used as an add-on treatment for drug-resistant partial epilepsy.ObjectiveTo evaluate the efficacy and safety of zonisamide as an adjunctive treatment for people with drug-resistant partial epilepsy.Search methodsWe searched the English databases from PubMed, CENTRAL and the Chinese databases from CNKI, VIP, CBM. No time limit.Selection criteriaRandomized placebo controlled adjunctive trials of zonisamide for people with drug-resistant partial epilepsy.Data collection and analysisWe selected trials for inclusion and extracted data. Outcomes were:(1)50%or greater reduction in total seizure frequency;(2) treatment withdrawal;(3) adverse events. Summary odds ratio (OR) and95%confidence intervals(CIs) were estimated for each outcome.ResultsSeven trials (1467participants) were included. The overall OR with95%CI for50%reduction in seizure frequency compared to placebo for100to600mg/day of zonisamide was2.40(95%CI1.89to3.05). The OR for300to600mg/day of zonisamide was2.46(95%CI1.93to3.12). The OR for zonisamide (300to600mg per day) in people with complex epilepsy was3.07(95%CI2.05to4.60). The OR for treatment withdrawal for100to600mg/day zonisamide compared to placebo was1.38(95%CI1.01to1.89), and for300to600mg per day was1.55(95%CI1.13to2.11). The CIs of the following adverse effects indicate that they are significantly associated with zonisamide:somnolence1.49(95%CI1.01to2.20) and anorexia2.97(95%CI1.78to4.96).ConclusionZonisamide has efficacy as an adjunctive treatment in people with drug-resistant partial epilepsy, especially in people with drug-resistant complex partial epilepsy. Patients are significantly more likely to withdraw from zonisamide than from placebo. The more frequent adverse effects are somnolence and anorexia in zonisamide than placebo. It’s not sure if zonisamide has effects on patients’ quality of life. The trials reviewed were of short duration and results cannot be used to confirm longer periods of effectiveness in seizure control. The results cannot be extrapolated to monotherapy or to people with other seizure types or epilepsy syndromes.