Phenytoin
- Oral / IVPhenytoinDilantin
Mechanism of Action
- Inhibits voltage-gated sodium channels, preventing propagation of action potentials and thus suppressing seizure activity.
- Pharmacology
- Non-linear pharmacokinetics - small dose changes can result in large changes in plasma concentration.
- Co-administration with valproate results in increased serum concentrations of phenytoin
Clinical Use
- Indications
- Generalised tonic-clonic seizures
- Status epilepticus (IV)
- Adverse Effects
- Nausea / vomiting
- Hirsutism
- CNS disturbances - drowsiness, tremor, dysarthria, diplopia
- Purple glove syndrome (IV) - distal limb discolouration, pain and swelling
- Anticonvulsant hypersensitivity syndrome (prolonged admin) - fever, rash, lymphadenopathy, hepatitis, myositis
Monitoring
- Plasma concentration should be monitored in order to ensure therapeutic effect.