Medicinehospital

Fosphenytoin

An injectable anti-seizure medicine for status epilepticus and seizures around neurosurgery.

Clinical information

Common uses

generalised tonic-clonic status epilepticus
prevent and treat seizures during neurosurgery
short-term substitute for oral phenytoin

Common side effects

itching
involuntary eye movements (nystagmus)
dizziness
sleepiness
unsteadiness (ataxia)

Cautions

boxed warning: fast infusion risks severe low blood pressure and arrhythmias
serious skin reactions — stop at first sign of rash
do not stop suddenly — can trigger status epilepticus
not with certain slow heart rhythms or heart block

Interactions

delavirdine (must not combine)
many drugs alter phenytoin levels via liver enzymes — levels monitored
drugs highly bound to blood proteins (caution)

Pregnancy: avoid if possible — risk of birth defects; specialist advice

Reference information, not medical advice — always follow your doctor or pharmacist. Source: DailyMed, dailymed.nlm.nih.gov, Fosphenytoin sodium injection label, setid bb38bc6a-99c7-4cda-b3f0-37f629d060cf (accessed 2026-08-16)

Approved brands & formulations2

Brand name	Dosage form	Strength	Importer	Category
Fosphenytoin	Parenteral ( Injection )	150mg	MFDA designated importers with Pre Authorization approval before import	hospital
Fosphenytoin	Parenteral ( Injection )	75 mg/ml	MFDA designated importers with Pre Authorization approval before import	hospital