TheraRadar
Data updated: May 26, 2026

METHSUXIMIDE

CNS Approved 2023-05-01

Methsuximide is an antiepileptic medication indicated for the control of absence (petit mal) seizures that are refractory to other treatments. It is a succinimide derivative typically reserved for patients who have not achieved adequate seizure control with first-line therapies.

Source: FDA Label • NOVITIUM PHARMA • Anti-epileptic Agent

How METHSUXIMIDE Works

Methsuximide exerts its therapeutic effect by suppressing the paroxysmal three-cycle-per-second spike-and-wave activity characteristic of absence seizures. At the cellular level, it acts by inhibiting T-type voltage-gated calcium channels in thalamic neurons. This inhibition reduces the thalamocortical oscillations that trigger absence seizures. Methsuximide is rapidly metabolized to its active metabolite, N-desmethylmethsuximide, which also contributes significantly to its anticonvulsant activity.

Source: FDA Label
1
Indication
--
Phase 3 Trials
3
Years on Market

Details

Status
Prescription
First Approved
2023-05-01
Routes
ORAL
Dosage Forms
CAPSULE

Companies

Active Ingredient: METHSUXIMIDE

METHSUXIMIDE Approval History

2024
2025
2026
Original
New Indication
New Form
Label Update
1 FDA actions from 2023 to 2023
May 2023 ORIGINAL
Update

What METHSUXIMIDE Treats

1 indications

METHSUXIMIDE is approved for 1 conditions since its original approval in 2023. These indications span multiple therapeutic areas including oncology, immunology, and more.

  • Seizures
Source: FDA Label

METHSUXIMIDE 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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Active Pipeline

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Key Completed Trials

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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.

METHSUXIMIDE FDA Label Details

Indications & Usage

METHSUXIMIDE is indicated for the treatment of Seizures.

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Data Sources

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