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Drug

Phenytoin

Established medicine
ClassSodium channel alpha subunit blockerResearchOngoing clinical research
Also known as DPH, Di-Phen, Dilantin, Diphenylhydantoin+13 more

DPH, Di-Phen, Dilantin, Diphenylhydantoin, Euthaphen, Euthasol, Fenitoina, Phenytek, Redox-phenytoin, Phentytoin, Phenytoine, 5,5-Diphenyl-imidazolidine-2,4-dione, 5,5-Diphenylhydantoin, 5,5-Diphenyltetrahydro-1H-2,4-imidazoledione, 5,5-diphenylimidazolidine-2,4-dione, Phenytoin Sodium, Phenytoinum.

RxNorm8183ChEMBLCHEMBL16ATCN03AB02ATCN03AB52UNII6158TKW0C5
6
Active clinical trials
10
Protein targets
1
Regulatory events
Latest activity
beta

Recent clinical, regulatory, research and industry developments relating to this drug.

An Open-Label, Parallel Group Study Designed to Investigate the Effect of the CYP3A Inducer Phenytoin and the CYP3A Inhibitor Itraconazole on the Pharmacokinetics of BGB-58067 in Healthy Participants

Clinical trial2026-07-09Results expected Q3 2026 · ClinicalTrials.gov

Correlation Between Phenotypic Activity of CYP2C9 and Genetic Polymorphism in CYP2C9 and Warfarin Metabolism.

Clinical trial2026-04-21Results expected Q4 2030 · ClinicalTrials.gov

Pharmacological Management of Seizures Post Traumatic Brain Injury (MAST)

Clinical trial2026-03-01Primary completion · ClinicalTrials.gov

A Phase 1, Open-Label Study to Evaluate the Relative Bioavailability and the Effect of Food on VH4524184 Tablet Formulations, and to Evaluate the Potential for VH4524184 Drug-Drug-Interactions in Healthy Adult Participants

Clinical trial2025-12-17Completed · ClinicalTrials.gov

A Phase 1, Open-Label, Fixed-Sequence, Drug-Drug Interaction Study of Casdatifan With Itraconazole (Strong CYP3A4 Inhibitor) and Phenytoin (Strong CYP3A4 Inducer) in Healthy Adult Participants

Clinical trial2025-10-18Completed · ClinicalTrials.gov

A Phase 1, Open-label, Fixed-sequence, Crossover Study to Investigate the Effect of Coadministration of the CYP3A Inducer Phenytoin and the CYP3A Inhibitor Itraconazole on the Pharmacokinetics of BGB-16673 in Healthy Participants

Clinical trial2025-10-13Completed · ClinicalTrials.gov

Assessing Phenytoin and Levetiracetam Efficacy, Cost-Effectiveness, and CYP2C9/SV2A Polymorphism in Early Post-Traumatic Seizures: A Multicentric Prospective Randomized Trial

Clinical trial2025-08-06Results expected Q1 2027 · ClinicalTrials.gov

An Open-Label, Phase 1 Study to Characterize the Effects of Phenytoin on the Pharmacokinetics of Belzutifan in Healthy Adult Participants

Clinical trial2025-05-27Completed · ClinicalTrials.gov

An Open-Label, Parallel Group Study Designed to Investigate the Effect of the CYP3A Inducer Phenytoin and the CYP3A Inhibitor Itraconazole on the Pharmacokinetics of Sonrotoclax (BGB-11417) in Healthy Subjects

Clinical trial2024-11-07Completed · ClinicalTrials.gov

A PHASE 1, OPEN-LABEL, RANDOMIZED, SINGLE-DOSE, 2-WAY CROSSOVER, PIVOTAL BIOEQUIVALENCE STUDY COMPARING 50-MG CHEWABLE DILANTIN® INFATABS® MANUFACTURED AT VEGA BAJA (PUERTO RICO) AND ASCOLI (ITALY) IN HEALTHY ADULT PARTICIPANTS UNDER FASTING CONDITIONS

Clinical trial2024-10-04Completed · ClinicalTrials.gov

A Phase 1, Open-label, 4-Part, Drug-Drug Interaction Study to Evaluate the Effects of Inhibition and Induction of CYP3A4 on the Pharmacokinetics of Leramistat, to Assess the Effect of Leramistat on the Pharmacokinetics of Simvastatin, and to Evaluate the Pharmacokinetic Interaction Between Leramistat and Upadacitinib (RINVOQ®) in Healthy Adult Subjects

Clinical trial2024-09-30Primary completion · ClinicalTrials.gov

Drug Safety Update: Phenytoin: risk of Stevens-Johnson syndrome associated with HLA-B*1502 allele in patients of Thai or Han Chinese ethnic origin

Regulatory2014-12-11MHRA

Profile

Identifiers & mechanism

Canonical identifiers, marketed brand names and mechanism, resolved across RxNorm, ChEMBL and ATC.

Canonical name
Phenytoin
Aliases & brands
DPHDi-PhenDilantinDiphenylhydantoinEuthaphenEuthasolFenitoinaPhenytekRedox-phenytoinPhentytoinPhenytoine5,5-Diphenyl-imidazolidine-2,4-dione5,5-Diphenylhydantoin5,5-Diphenyltetrahydro-1H-2,4-imidazoledione5,5-diphenylimidazolidine-2,4-dionePhenytoin SodiumPhenytoinum
RxNorm CUI
8183
ChEMBL ID
CHEMBL16
ATC codes
N03AB02N03AB52
UNII
6158TKW0C5
Primary mechanism
Sodium channel alpha subunit blocker
Regulatory jurisdictions
mhra

Pharmacology & targets

10 targets

Known molecular targets and mechanisms supported by curated pharmacology databases.

Sodium channel protein type 1 subunit alpha
SCN1A · P35498
BLOCKERSodium channel alpha subunit blocker
Sodium channel protein type 5 subunit alpha
SCN5A · Q14524
BLOCKERSodium channel alpha subunit blocker
Sodium channel protein type 4 subunit alpha
SCN4A · P35499
BLOCKERSodium channel alpha subunit blocker
Sodium channel protein type 7 subunit alpha
SCN7A · Q01118
BLOCKERSodium channel alpha subunit blocker
Sodium channel protein type 2 subunit alpha
SCN2A · Q99250
BLOCKERSodium channel alpha subunit blocker
Sodium channel protein type 9 subunit alpha
SCN9A · Q15858
BLOCKERSodium channel alpha subunit blocker
Sodium channel protein type 3 subunit alpha
SCN3A · Q9NY46
BLOCKERSodium channel alpha subunit blocker
Sodium channel protein type 11 subunit alpha
SCN11A · Q9UI33
BLOCKERSodium channel alpha subunit blocker
Sodium channel protein type 8 subunit alpha
SCN8A · Q9UQD0
BLOCKERSodium channel alpha subunit blocker
Sodium channel protein type 10 subunit alpha
SCN10A · Q9Y5Y9
BLOCKERSodium channel alpha subunit blocker

Regulatory timeline

1 event

The complete regulatory record, grouped by authority — approvals, safety advisories and label changes. Each authority shows its most recent events; expand one to read its full history.

Authorities
MHRA
Total events
1
mhraMedicines and Healthcare products Regulatory Agency· 1 event
2014-12-11Safety communicationSafety
Drug Safety Update: Phenytoin: risk of Stevens-Johnson syndrome associated with HLA-B*1502 allele in patients of Thai or Han Chinese ethnic origin
Evidence ↗

Contains public sector information from the Medicines and Healthcare products Regulatory Agency (MHRA) licensed under the Open Government Licence (OGL v3).

Clinical trials

53 trials

The current development programme across all trial phases — status mix, phase distribution and the late-stage studies shaping the evidence base.

Development programme
CLINICALTRIALS.GOV · LIVE REGISTRY
53
registered trials across all phases
LATEST COMPLETION 2025
6
Active studies
6
Recruiting
24
Late-stage (III+)
33
Completed
14
Discontinued
PHASE DISTRIBUTIONn = 53
Early Phase 11Phase 119Phase 1 / 22Phase 27Phase 36Phase 412Phase N / A6

Late-stage studies

Phase III+ trials still open or recently active — where late-stage evidence is being generated.

Assessing Phenytoin and Levetiracetam Efficacy, Cost-Effectiveness, and CYP2C9/SV2A Polymorphism in Early Post-Traumatic Seizures: A Multicentric Prospective Randomized Trial

RecruitingPH IVKey trialAll India Institute of Medical Sciences, Jodhpurn=1,2602028

The Efficacy and Safety of First-Line Anti-Epileptic Drugs (AEDs) as Substitution Therapy in Children Who Are Resistant to Second-Line AEDs

Unknown statusPH IVDr Cipto Mangunkusumo General Hospitaln=1002023

Levetiracetam Versus Phenytoin in Management of Pediatric Status Epilepticus: a Randomized Clinical Trial

Unknown statusPH IVTanta Universityn=602020

Phenytoin for Memory Impairment Secondary to Megestrol

CompletedPH IVUniversity of Texas Southwestern Medical Centern=212016

Efficacy of Phenytoin in the Prophylaxis of Seizures of Patients With Pneumococcal Meningitis at Least 50 Yrs Old. A Multi-center Comparative Randomized Double-blind and Placebo-controlled Clinical Trial

TerminatedPH IVM. Carmen Cabellos Minguezn=262015

Recent completions

Trials that read out recently, adding to the completed evidence base.

A Phase 1, Open-Label Study to Evaluate the Relative Bioavailability and the Effect of Food on VH4524184 Tablet Formulations, and to Evaluate the Potential for VH4524184 Drug-Drug-Interactions in Healthy Adult Participants

CompletedPH IViiV Healthcaren=1262025

A Phase 1, Open-Label, Fixed-Sequence, Drug-Drug Interaction Study of Casdatifan With Itraconazole (Strong CYP3A4 Inhibitor) and Phenytoin (Strong CYP3A4 Inducer) in Healthy Adult Participants

CompletedPH IArcus Biosciences, Inc.n=142025

A Phase 1, Open-label, Fixed-sequence, Crossover Study to Investigate the Effect of Coadministration of the CYP3A Inducer Phenytoin and the CYP3A Inhibitor Itraconazole on the Pharmacokinetics of BGB-16673 in Healthy Participants

CompletedPH IBeiGenen=372025

An Open-Label, Phase 1 Study to Characterize the Effects of Phenytoin on the Pharmacokinetics of Belzutifan in Healthy Adult Participants

CompletedPH IMerck Sharp & Dohme LLCn=142025

An Open-Label, Parallel Group Study Designed to Investigate the Effect of the CYP3A Inducer Phenytoin and the CYP3A Inhibitor Itraconazole on the Pharmacokinetics of Sonrotoclax (BGB-11417) in Healthy Subjects

CompletedPH IBeiGenen=302024

A PHASE 1, OPEN-LABEL, RANDOMIZED, SINGLE-DOSE, 2-WAY CROSSOVER, PIVOTAL BIOEQUIVALENCE STUDY COMPARING 50-MG CHEWABLE DILANTIN® INFATABS® MANUFACTURED AT VEGA BAJA (PUERTO RICO) AND ASCOLI (ITALY) IN HEALTHY ADULT PARTICIPANTS UNDER FASTING CONDITIONS

CompletedPH IPfizern=352024
References & data sources
  • RxNorm (U.S. National Library of Medicine) — drug identity
  • ChEMBL (EMBL-EBI) & UniProt — pharmacology and targets
  • ClinicalTrials.gov — clinical trials
  • Regulatory event sources are credited in the Regulatory Timeline above.