API

Phenytoin (25mg/ml)

Drug classification

Anticonvulsants (hydantoin anticonvulsant)

Dosage form

Oral suspension

API strength per dosage

25 mg per 1 ml

Dose

Adults: Initially 100 mg (4 mL) three times daily; adjust to maintenance 300–400 mg/day in divided doses. Children: 5 mg/kg/day in two or three divided doses; maintenance 4–8 mg/kg/day. Elderly or hepatic impairment: Use lower initial doses and titrate cautiously. Adjust for renal/hepatic impairment as needed.

Mechanism of action

Binds and stabilizes the inactivated state of voltage-gated sodium channels (Nav1.1–Nav1.6), reducing neuronal membrane excitability and repetitive firing by inhibiting sustained high-frequency action potentials, thereby limiting seizure propagation.

Indications

Treatment and prevention of Epilepsy/Seizures

Side effects

Rash Headache Dizziness Vomiting Nausea Slurred speech Vertigo Confusion Nervousness Constipation Tremors Altered walking

Pregnancy category

Precautions

Contraindications