TheraRadar
Data updated: May 26, 2026

ZONISADE (zonisamide)

Carbonic Anhydrase Inhibitors Trial Activity: Declining 1 active trials
CNS Approved 2022-07-15

ZONISADE (zonisamide) is an anti-epileptic agent indicated for use as an adjunctive therapy. It is approved for the treatment of partial-onset seizures in both adults and pediatric patients 16 years of age and older. As an adjunctive treatment, it is used in combination with other therapies to manage seizure activity in these patient populations.

Source: FDA Label • AZURITY • Anti-epileptic Agent

How ZONISADE Works

The exact mechanism of zonisamide's anticonvulsant effects is unknown, but it is thought to act on sodium and calcium channels. By blocking sodium channels and reducing voltage-dependent, transient inward calcium currents, the drug helps stabilize neuronal membranes. It also suppresses synaptically-driven electrical activity and acts as a carbonic anhydrase inhibitor, though the therapeutic contribution of the latter is not established.

Development Insights

Eisai Limited conducting 4 trials (16%)
21 indications explored (Broad Platform)
epilepsy (6 trials)
alcohol dependence (3 trials)
alcohol use disorder (3 trials)
1
Indication
--
Phase 3 Trials
3
Years on Market

Details

Status
Prescription
First Approved
2022-07-15
Patent Cliff
2038

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Routes
ORAL
Dosage Forms
SUSPENSION

Companies

Active Ingredient: ZONISAMIDE

ZONISADE Approval History

2023
2024
2025
2026
Original
New Indication
New Form
Label Update
1 FDA actions from 2022 to 2022
Jul 2022 ORIGINAL
New Form · Type 3 - New Dosage Form

What ZONISADE Treats

1 indications

ZONISADE is approved for 1 conditions since its original approval in 2022. These indications span multiple therapeutic areas including oncology, immunology, and more.

  • Partial-Onset Seizures
Source: FDA Label

ZONISADE Competitive Set

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Filters applied: drops same-active-ingredient (505(b)(2) reformulations), route-mismatch (topical vs systemic), and cross-therapeutic-area matches in same-indication rings.

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Clinical Trial Registry

24 trials
Trial Sponsor ID Phase Status Title
NCT05205811 BuZonE 2 Ph 3 completed The Effects of Combination Zonisamide and Bupropion on Switching to an Electronic Cigarette
NCT05134857 18520-001 Ph 2 recruiting The Zonisamide and Reinforcement for Reducing Alcohol Use (ZARRA) Study
NCT02901041 results posted 2R01AA015923-06 Ph 3 completed Interdisciplinary Study of A Novel Anticonvulsant in Alcoholism
NCT02900352 Z-Comp results posted HM20014185 1605017700, 7R01AA024466-04 Ph 3 completed Zonisamide Treatment of Alcohol Use Disorder: an Evaluation of Efficacy and Mechanism of Action
NCT01766128 ZONIST ZEPD-1091 Ph 2, Ph 3 withdrawn Study of Zonisamide in Early Parkinson Disease
NCT04388319 BuZonE results posted BuZonE Ph 3 completed Zonisamide/Bupropion Effects on Switching to Electronic Cigarettes
NCT01140867 results posted E2090-S082-409 Ph 4 completed Open-label, Multi-center Trial of Zonisamide as Adjunctive Therapy in Patients With Uncontrolled Partial Epilepsy
NCT03376139 AS140026-A4 W81XWh-15-2-0077 Ph 2 withdrawn Zonisamide Outpatient Study
NCT02368431 results posted CLNA-003-14S ICX001012A Ph 3 terminated Effectiveness of Zonisamide in Alcohol Dependent Veterans
NCT01847469 results posted 1211011063 01641 Ph 2 completed Zonisamide in Addition to E-CPT-C for Veterans With PTSD and Comorbid Alcohol Dependence
NCT01685996 1207 results posted NA_00074143 R21DA034164 Ph 1, Ph 2 completed Zonisamide Augmentation of Varenicline Treatment for Smoking Cessation
NCT02049073 NIHL2014 Ph 1, Ph 2 withdrawn Prevention of Noise-induced Hearing Loss
NCT01137890 results posted R01DA027065 R01DA027065 Ph 1, Ph 2 completed Effect of Zonisamide on Cocaine Reinforcement, Craving, and Relapse
NCT00692003 results posted E2090-E044-315 Eudra ID #2007-003557-91. Ph 3 terminated Adjunctive Zonisamide in Primary Generalised Tonic Clonic Seizures
NCT01566370 ZNSBP results posted ZNS-BP VACT MIRECC, K23AA017689 Ph 2 terminated Zonisamide for Heavy Drinkers With Bipolar Disorder
NCT01136954 results posted E2090-E044-313 2007-000198-53 Ph 3 completed A Study to Assess the Efficacy and Safety of Adjunctive Zonisamide in Paediatric Partial Onset Seizures (CATZ Extension Study)
NCT00693017 results posted E2090-E044-317 2007-003556-10 Ph 3 terminated Efficacy and Safety of Adjunctive Zonisamide in Myoclonic Seizures Associated With Idiopathic Generalised Epilepsy
NCT00848549 results posted E2090-E044-314 2008-001159-23 Ph 3 completed Assessing The Long-Term Safety And To Explore The Long-Term Efficacy Of Zonisamide As Monotherapy In Newly Diagnosed Partial Seizures
NCT00713622 E2090-E044-406 2007-005313-19 Ph 4 completed Comparing The Effect On Cognition Of Adjunctive Therapy With Zonisamide Versus Sodium Valproate
NCT00862563 results posted NIAAA-CIR-AA015923 P60AA013759, 1R01AA015923 Ph 2 terminated Interdisciplinary Study of Two Novel Anticonvulsants in Alcoholism
NCT01765608 ZON-01 2009-015859-24 Ph 2 completed Zonisamide for the Treatment of Obstructive Sleep Apnea in Overweight/Obese Patients
NCT00659958 E2090-E044-407 Ph 4 completed ZAGAL Study: Evaluating Effectiveness and Tolerability of Zonisamide as Adjunctive Therapy in Patients With Partial Onset Seizures Treated With Two Antiepileptic Drugs
NCT00566254 results posted E2090-E044-312 2006-002515-27 Ph 3 completed Efficacy and Safety of Adjunctive Zonisamide in Paediatric Partial Onset Seizures (CATZ Study)
NCT00363376 06-06-14-01 F1D-MC-X269 Ph 3 completed A Study of Zonisamide to Prevent Olanzapine-Associated Weight Gain
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Active Pipeline

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Key Completed Trials

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Completed studies with published results, ranked by significance

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Trial Timeline

Full development history with FDA approval milestones

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Understanding FDA Approval Types
Count Type What it means
- ORIG Original approval - drug first enters market
- SUPPL - Efficacy New indication (new disease/condition approved)
- SUPPL - Labeling Label text changes (warnings, dosing updates)
- SUPPL - Manufacturing Production changes (new facility)
- SUPPL - Chemistry Formulation changes (new dosage strength)

Green lines in the timeline show ORIG and Efficacy approvals - the clinically meaningful milestones.

ZONISADE FDA Label Details

Indications & Usage

FDA Label (PDF)

ZONISADE is indicated for the treatment of Partial-Onset Seizures.

View full patent landscape →
3 OB patents · 1 families · 12 international docs across 3 countries

ZONISADE Patents & Exclusivity

Latest Patent: Aug 2038

Patents (3 active)

US11478456 Expires Aug 18, 2038
US12491179 Expires Aug 18, 2038
US11529333 Expires Aug 18, 2038
Source: FDA Orange Book

Pro Intelligence Preview

Deep insights for ZONISADE

Revenue Insights

  • Quarterly revenue tracking
  • Historical trend analysis

Patent Timeline

  • Cliff: 2038
  • 3 active patents

Trial Analysis

  • 25 total trials
  • Stage: Declining

Competitive Landscape

  • 20 similar drugs
  • Same target/indication analysis
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Data Sources

Data sourced from official FDA and NIH databases. Click links to verify on original sources.

How We Calculate These Metrics

Trial Activity Stage

Measures the current development activity pattern based on trial phases, status, and trends. Important: This measures R&D activity, not commercial lifecycle.

Trial statuses: "Active" means recruiting or ongoing. "Completed" means reached planned endpoint. "Terminated" means stopped early—often due to safety, efficacy, or business reasons.

  • Growth: High proportion of early-phase trials (Phase 1/2), active development
  • Expansion: Significant Phase 3 activity, approaching or pursuing approvals
  • Mature: Substantial Phase 4 post-marketing studies
  • Stable: Mixed phase distribution, steady development
  • Declining: Low active trial ratio, reduced R&D investment