Phenytoin prodrug (anticonvulsant)

Fosphenytoin sodium

Brand names: Pro-Epanutin

Adult dose

Dose: Doses expressed as PE (phenytoin equivalents). Status epilepticus: loading 20mg PE/kg IV at up to 150mg PE/min; maintenance 4–5mg PE/kg/day

Route: IV/IM

Frequency: loading + maintenance

Clinical pearls

Less infusion-site complications than phenytoin
Faster delivery rate possible (150 mg PE/min vs 50 mg/min phenytoin)

Contraindications

Sinus bradycardia
SA/AV block
Adams-Stokes syndrome
Acute porphyria

Side effects

Hypotension/arrhythmia (slower onset than IV phenytoin)
Pruritus/paraesthesia (transient)
Nystagmus
Ataxia

Interactions

Many — strong CYP inducer
Warfarin (variable)
OCP
Other AEDs

Monitoring

ECG
BP during loading
Phenytoin levels post-loading

Reference: BNF; NICE NG217; UK status epilepticus algorithms; https://bnf.nice.org.uk/drugs/fosphenytoin-sodium/. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways