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Phenytoin

Epanutin, Epilan-D · ATC code N03AB02

Also known as: fenitoin · Brand names: Epanutin, Epilan-D, Phenhydan, Phenytoin Awd, Phenytoin Hikma, Epdantoin, Epitoin, Fenilepsy, Fenitosel, Hidantin, Toinex, Dilantin, Dilantin Infatabs, Dilantin-125, Extended Phenytoin Sodium …

Key facts
Active substance
Phenytoin
Drug class
Anticonvulsant agent
ATC code
N03AB02
Authorisation
authorised nationally; no central EU authorisation
Information as of
2026-10-27

Key facts

Phenytoin is a hydantoin antiepileptic. Per the US label it is used for tonic-clonic and psychomotor seizures and for seizures related to neurosurgery.

What it is used for

  • Tonic-clonic (grand mal) and psychomotor (temporal lobe) seizures
  • Prevention and treatment of seizures during or following neurosurgery

Dosing

  • Untreated adults: start 100 mg three times daily; usual maintenance 100 mg three to four times daily; maximum two capsules three times daily
  • If controlled on 300 mg daily in divided doses, once-daily 300 mg may be considered (extended capsules only)
  • Oral loading (clinic or hospital with level monitoring; not in renal or liver disease): one gram in three doses (400 mg, 300 mg, 300 mg) at two-hour intervals
  • Children: start 5 mg/kg/day in two or three doses; maintenance usually 4 mg/kg/day to 8 mg/kg/day, maximum 300 mg daily
  • Therapeutic total serum level usually 10 mcg/mL to 20 mcg/mL; monitor levels when changing product

Contraindications

  • Hypersensitivity to phenytoin, inactive ingredients or other hydantoins
  • Prior acute hepatotoxicity attributable to phenytoin
  • Coadministration with delavirdine

Important warnings

  • Abrupt withdrawal may precipitate status epilepticus; reduce gradually
  • Increased risk of suicidal thoughts and behavior
  • Serious skin reactions (SJS, TEN, DRESS), which may be fatal; HLA-B*1502 a possible risk factor
  • Bradycardia and cardiac arrest, hepatic injury, hematopoietic complications
  • Teratogenicity; effects on vitamin D and bone; hyperglycemia

Side effects

  • Most common, usually dose-related: nystagmus, ataxia, slurred speech, decreased coordination, somnolence, mental confusion
  • Others: dizziness, insomnia, headache, paresthesias
  • Serious: severe skin reactions, liver injury, blood disorders

Interactions

  • Highly protein bound with saturable metabolism by CYP2C9 and CYP2C19: inhibitors can markedly raise levels; monitor serum levels
  • Phenytoin is a potent enzyme inducer and can lower levels of other drugs
  • Delavirdine: contraindicated

Pregnancy and breastfeeding

  • Prenatal exposure increases the risk of malformations (e.g. orofacial clefts, cardiac defects) and fetal hydantoin syndrome
  • Phenytoin is secreted in human milk

Summary of the official product information, written with AI (Claude, Anthropic) on 2026-10-28. Every number was checked automatically against the original text. Not reviewed by a physician – the full official text is authoritative.

Full official text →

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For patients

Patient information (US)

Patient information (US) →

Authorisation and brand names by country

Medicines with exactly this active-substance composition, as listed in the national registers – alphabetical and without ranking. Whether a product is currently available is not shown here.

Austria

  • EpanutinViatris Austria Gmbh · 1 register entry
  • Epilan-DG.L. Pharma Gmbh · 2 register entries

Source: EMA – Article 57 product data (EU/EEA), as of 2026-10-28

Germany

  • PhenhydanDesitin Arzneimittel Gmbh · 2 register entries
  • Phenytoin AwdTeva Gmbh · 1 register entry
  • Phenytoin HikmaHikma Farmacêutica (Portugal), S.A. · 1 register entry

Source: EMA – Article 57 product data (EU/EEA), as of 2026-10-28

Turkey

  • EpanutinVİATRİS İLAÇLARI LİMİTED ŞİRKETİ · 1 register entry
  • EpdantoinEXELTIS İLAÇ SAN. VE TİC. A.Ş. · 1 register entry
  • EpitoinVEM İLAÇ SAN. VE TİC. A.Ş. · 1 register entry
  • FenilepsyTÜRKEM İLAÇ SAN. VE TİC. A.Ş. · 1 register entry
  • FenitoselHAVER FARMA İLAÇ A.Ş. · 1 register entry
  • HidantinSİFAR İLAÇLARI TİC. VE SAN. A.Ş. · 1 register entry
  • ToinexHAVER TRAKYA İLAÇ SAN. VE TİC. A.Ş. · 1 register entry

Source: TİTCK – Ruhsatlı Beşeri Tıbbi Ürünler Listesi, as of 2026-10-16

USA

  • DilantinViatris Specialty LLC · 2 register entries
  • Dilantin InfatabsParke-Davis Div of Pfizer Inc · 1 register entry
  • Dilantin-125Viatris Specialty LLC · 1 register entry
  • Extended Phenytoin SodiumAurobindo Pharma Limited, Amneal Pharmaceuticals LLC · 6 register entries
  • PhenytekMylan Pharmaceuticals Inc. · 2 register entries

Source: U.S. FDA – Drug labels (openFDA/DailyMed), as of 2026-10-28

Brand names in 19 more European countries
Belgium
Diphantoïne
Cyprus
Epanutin, Fenitoína Rubió
Czechia
Epanutin Parenteral, Epilan D
Estonia
Phenhydan
Finland
Hydantin
France
Di-Hydan, Dilantin
Greece
Epanutin
Hungary
Diphedan, Epanutin
Ireland
Epanutin
Italy
Aurantin, Dintoina, Fenitoina Hikma
Luxembourg
Diphantoïne
Malta
Epanutin
Netherlands
Diphantoine-Z, Diphantoïne-Z, Epanutin Ready Mixed, Fenytoïne Desitin
Poland
Epanutin Parenteral, Phenytoin Hikma, Phenytoinum Wzf
Portugal
Fenitan, Fenitoína Accord, Fenitoína Generis, Fenitoína Hikma, Fenitoína Labesfal, Hidantina
Romania
Fenitoină Richter, Phenhydan
Slovakia
Epilan D
Spain
Epanutin, Fenitoína Altan Pharmaceuticals S.A., Fenitoína Rubió, Sinergina
Sweden
Epanutin

EMA – Article 57 product data (EU/EEA), 2026-10-28

Medelix receives no money from pharmaceutical companies. Brand names are listed alphabetically and without ranking.

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Sources

  1. U.S. Food and Drug Administration. Phenytoin Sodium (Sun Pharmaceutical Industries, Inc.) – Prescribing Information, 2026-03-17. DailyMed (NLM), 2026-10-27. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=601f7353-225d-4a5d-9810-3869c2c21874
  2. EMA – Article 57 product data (EU/EEA), 2026-10-28. https://www.ema.europa.eu/en/human-regulatory-overview/post-authorisation/data-medicines-iso-idmp-standards-post-authorisation/public-data-article-57-database
  3. EMA – Article 57 product data (EU/EEA), 2026-10-28. https://www.ema.europa.eu/en/human-regulatory-overview/post-authorisation/data-medicines-iso-idmp-standards-post-authorisation/public-data-article-57-database
  4. TİTCK – Ruhsatlı Beşeri Tıbbi Ürünler Listesi, 2026-10-16. https://www.titck.gov.tr/dinamikmodul/85
  5. U.S. FDA – Drug labels (openFDA/DailyMed), 2026-10-28. https://dailymed.nlm.nih.gov/dailymed/
  6. Wikidata (CC0): ATC N03AB.

Editorial: Medelix editorial team · last updated 2026-10-27 · How these pages are made · Report an error

Source: U.S. Food and Drug Administration (FDA), prescribing information, via DailyMed (NLM); public domain. Not advertising, not a treatment recommendation. For questions about your own treatment, ask your doctor or pharmacist.