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Data updated: May 26, 2026

DILANTIN (phenytoin sodium)

CNS Approved 1956-03-01

DILANTIN is indicated for the treatment of Tonic-Clonic Seizures; Psychomotor Seizures.

Source: FDA Label • Viatris

How DILANTIN Works

The precise mechanism of this medication has not been established, but it is thought to involve the voltage-dependent blockade of membrane sodium channels. This blockade results in a reduction in sustained high-frequency neuronal discharges. By limiting these discharges, the drug exerts its therapeutic effect in the treatment and prevention of seizures.

3
Indications
--
Phase 3 Trials
70
Years on Market

Details

Status
Prescription
First Approved
1956-03-01
Routes
ORAL, INJECTION
Dosage Forms
CAPSULE, INJECTABLE, TABLET, CHEWABLE

Companies

Active Ingredient: PHENYTOIN SODIUM

DILANTIN Approval History

1957
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Original
New Indication
New Form
Label Update
159 FDA actions from 1956 to 2023
May 2023 SUPPL
Label · Labeling
Sep 2022 SUPPL
Label · Labeling
Oct 2021 SUPPL
Label · Labeling

What DILANTIN Treats

2 indications

DILANTIN is approved for 2 conditions since its original approval in 1956. These indications span multiple therapeutic areas including oncology, immunology, and more.

  • Tonic-Clonic Seizures
  • Psychomotor Seizures
Source: FDA Label

DILANTIN 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.

Drugs Similar to DILANTIN

3 of 4

FDA-approved drugs for similar conditions. Compare mechanisms and indications to understand treatment alternatives.

DILANTIN-125
PHENYTOIN
2 shared
Viatris
Shared indications:
Tonic-Clonic SeizuresPsychomotor Seizures
PHENYTEK
PHENYTOIN SODIUM
2 shared
Viatris
Shared indications:
Tonic-Clonic SeizuresPsychomotor Seizures
MOTPOLY XR
LACOSAMIDE
1 shared
AUCTA
Shared indications:
Tonic-Clonic Seizures
📋

Clinical Trial Registry

1 trials
Trial Sponsor ID Phase Status Title
NCT04573803 MAST A095460 Ph 3 not yet recruiting Pharmacological Management of Seizures Post Traumatic Brain Injury
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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.

DILANTIN FDA Label Details

Indications & Usage

FDA Label (PDF)

DILANTIN is indicated for the treatment of Tonic-Clonic Seizures; Psychomotor Seizures.

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Data Sources

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