Overview
Lamotrigine is an anticonvulsant medication used primarily for epilepsy and bipolar disorder. It works by stabilizing neuronal membranes and inhibiting the release of excitatory neurotransmitters. Lamotrigine is considered a broad-spectrum antiepileptic drug with mood-stabilizing properties.
Mechanism of Action
Lamotrigine inhibits voltage-sensitive sodium channels, stabilizing neuronal membranes and modulating presynaptic glutamate and aspartate release. This results in decreased excitatory neurotransmitter activity in the brain.
Indications
- Epilepsy: Partial seizures and generalized tonic-clonic seizures
- Bipolar I Disorder: Maintenance treatment to prevent mood episodes
- Lennox-Gastaut syndrome
Dosage
Dosage varies by indication and patient factors. For epilepsy: Start 25mg daily for 2 weeks, then 50mg daily for 2 weeks, then increase by 50mg weekly to maintenance dose of 100-200mg daily (monotherapy) or 200-400mg daily (with enzyme-inducing drugs). For bipolar disorder: Start 25mg daily for 2 weeks, then 50mg daily for 2 weeks, then 100mg daily for 1 week, then 200mg daily. Always follow specific titration schedules to minimize rash risk.
Contraindications
- Hypersensitivity to lamotrigine or any component
- History of serious rash or Stevens-Johnson syndrome with lamotrigine use
Side Effects
- Headache
- Dizziness
- Diplopia
- Nausea
- Somnolence
- Rash (including serious dermatological reactions)
- Insomnia
- Coordination abnormalities
- Blurred vision
- Vomiting
Interactions
- Valproate: Increases lamotrigine levels, requires dosage adjustment
- Carbamazepine, phenytoin, phenobarbital: Decrease lamotrigine levels
- Oral contraceptives: May decrease lamotrigine efficacy
- Other CNS depressants: Additive sedation effects