| Mechanism | Alters transmembrane movement of Na+/K+ by blocking voltage-gated Na+ channels - prevents spread of epileptic discharges |
| Typical Dose | 3-4mg/kg daily |
| Indications | * Epilepsy (all except absence seizure) * Trigeminal neuralgia |
| Contra-indications | Acute porphyrias |
| Side-effects | Common: dizziness, headache, confusion, insomnia, nausea, vomiting, hirsutism Rarely: gum hypertrophy, rash, Stevens-Johnson syndrome, drug-induced SLE |
| Interactions | Induces hepatic drug-metabolising enzymes: * Amiodarone, Aspirin, cimetidine, diltazem, nifedipine * OCP - increased metabolism of OCP * Rifampicin - plasma concentration of phenytoin * Warfarin - increased metabolism of Warfarin |
| Elimination | |
| Additional Notes | |