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fosphenytoin

Prodrug (of phenytoin) · Antiepileptic, Antiseizure Agent

Prodrug (of phenytoin)Antiepileptic, Antiseizure Agent
CDSCO approved
EXCRETION
—
not curated
INTERACTIONS
12 major
SEVERE in our sources
PREGNANCY
—
not curated
Top interactionssee all 12 →
  • AbemaciclibSevereDatabaseDDInter
  • AbirateroneSevereDatabaseDDInter
  • AcalabrutinibSevereDatabaseDDInter
  • AlpelisibSevereDatabaseDDInter

Mechanism

Not yet extracted

Indications

focal seizuresgeneralized seizuresstatus epilepticus

Dosing

Adult
150 mg/min IV (max 1000 mg or 15-20 mg/kg)
Pediatric
15-20 mg/kg IV (max 1000 mg or 15-20 mg/kg)

Pharmacokinetics

Half-life
8 to 15 min
Protein binding
95%–99% to human plasma proteins, primarily albumin

Side effects

Common
less damaging to the intima compared to phenytoinminor vascular complications
Serious
  • cardiac arrhythmias
  • hypotension
  • CNS depression

Drug interactions

Abemaciclib
Severe
Database

Drug interaction classified as: metabolism

Source: DDInter

Abiraterone
Severe
Database

Drug interaction classified as: metabolism

Source: DDInter

Acalabrutinib
Severe
Database

Drug interaction classified as: metabolism

Source: DDInter

Alpelisib
Severe
Database

Drug interaction classified as: metabolism

Source: DDInter

Amiodarone
Severe
Database

Drug interaction classified as: metabolism

Source: DDInter

Amlodipine
Severe
Database

Drug interaction classified as: metabolism

Source: DDInter

Apixaban
Severe
Database

Drug interaction classified as: metabolism

Source: DDInter

Apremilast
Severe
Database

Drug interaction classified as: metabolism

Source: DDInter

Artemether
Severe
Database

Drug interaction classified as: metabolism

Source: DDInter

Avapritinib
Severe
Database

Drug interaction classified as: metabolism

Source: DDInter

Avatrombopag
Severe
Database

Drug interaction classified as: metabolism

Source: DDInter

Axitinib
Severe
Database

Drug interaction classified as: metabolism

Source: DDInter

Related guidelines

Status epilepticus
AAN · Neurology · 2020
Initial monotherapy for newly diagnosed epilepsy
ILAE · Neurology · 2013
Functional (psychogenic non-epileptic) seizures
AAN · Neurology · 2026
Initial monotherapy for newly diagnosed epilepsy
IAN · Neurology · 2023
Hypothyroidism in adults
ITS · Endocrinology · 2021

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Sources: KD Tripathi 7e, Goodman & Gilman 14e·Verified: 2026-05-10 · House clinical team