What it's for (Indications)
- Lamotrigine is indicated for partial seizures, primary and secondarily generalized tonic clonic seizures (brain disorder/epilepsy).
- It is used as adjunctive therapy in epilepsy and for conversion to monotherapy.
- Additionally, it is indicated for bipolar disorder.
Dosage Information
| Type | Guideline |
|---|---|
| Standard | Dosing is individualized based on concomitant medications, indication, and patient age. To avoid an increased risk of rash, the recommended initial dose and subsequent dose escalations must not be exceeded. Discontinuation requires gradual tapering, typically over at least 2 weeks (approximately 50% dose reduction per week). Adjustments to maintenance doses are often required when patients initiate or discontinue estrogen-containing oral contraceptives. Specific dosage schedules for epilepsy (adjunctive therapy, monotherapy conversion, different age groups) and bipolar disorder are detailed in comprehensive clinical guidelines and product information. |
Safety & Warnings
Common Side Effects
- Common side effects include headaches, dizziness, tiredness (somnolence), insomnia (inability to sleep), gastrointestinal (GI) disturbances (e.
- g.
- , nausea), diplopia (double vision), ataxia, blurred vision, rhinitis, pharyngitis, and rash.
- Patients experiencing persistent or prolonged symptoms should consult their doctor.
Serious Warnings
- Black Box Warning: WARNING: SERIOUS SKIN RASHES. Lamotrigine can cause serious rashes requiring hospitalization and discontinuation of treatment, including Stevens-Johnson syndrome. The incidence is approximately 0.3% to 0.8% in pediatric patients (2-17 years) and 0.08% to 0.3% in adults. Rash-related deaths have been reported.
- Serious warnings include Hemophagocytic Lymphohistiocytosis, Multiorgan Hypersensitivity Reactions and Organ Failure, Cardiac Rhythm and Conduction Abnormalities, Blood Dyscrasias, Suicidal Behavior and Ideation, Aseptic Meningitis, Withdrawal Seizures, and Status Epilepticus.
- This medication should be avoided in patients with significant hepatic (liver) impairment.
- Hepatic, renal, and clotting parameters should be monitored in patients developing rash, fever, flu-like symptoms, or drowsiness.
- Pregnancy: Consult a doctor.
- Lactation: Avoid breastfeeding.
- Driving: Avoid driving as it may affect ability.
- Alcohol: Avoid consumption.
- Do not restart lamotrigine if discontinued due to rash, unless potential benefits clearly outweigh risks.
- Adjustments to maintenance doses are necessary when starting or stopping estrogen-containing oral contraceptives.
- Discontinuation should be gradual, tapering over at least 2 weeks (approximately 50% dose reduction per week).
How it Works (Mechanism of Action)
The precise mechanism(s) by which lamotrigine exerts its anticonvulsant action are unknown. In animal models, it effectively prevented seizure spread. A proposed mechanism, whose relevance to human epilepsy is not fully established, involves inhibition of voltage-sensitive sodium channels, thereby stabilizing neuronal membranes and modulating presynaptic excitatory neurotransmitter release.