Class
- Antiepileptic drug (AED)
Lamotrigine
Commonly Prescribed for
(FDA approved in bold)
- Complex partial seizures (adjunctive for age 16 or older)
- Conversion to monotherapy for partial seizures in adults 16 or older
- Lennox-Gastaut syndrome aged 2 and older
- Maintenance of bipolar disorder
- Generalized tonic-clonic seizures including juvenile myoclonic epilepsy
- Absence seizures (children and adults)
- Temporal lobe epilepsy (children and adults)
- Migraine prophylaxis
- SUNCT (Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing)
- Trigeminal neuralgia
- Bipolar depression or mania
- Psychosis/Schizophrenia (adjunctive)
Lamotrigine
How the Drug Works
- A use-dependent blocker of voltage-sensitive sodium channels, preventing release of excitatory neurotransmitters such as glutamate and aspartate
- May inhibit gamma-aminobutyric acid (GABA) release and interact with calcium channels
- Weakly inhibits serotonin-3 receptors
Lamotrigine
How Long Until It Works
- Seizures – should decrease by 2 weeks at a specific dose, but slow titration can delay time to effective dose
- Headaches – weeks to months
- Mania – may take weeks to months
Lamotrigine
If It Works
- Seizures – goal is the remission of seizures. Continue as long as effective and well-tolerated. Consider tapering and slowly stopping after 2 years without seizures, depending on the type of epilepsy
- Headache – goal is a 50% or greater decrease in frequency or severity of pain or aura
Lamotrigine
If It Doesn’t Work
- Increase to highest tolerated dose
- Epilepsy: consider changing to another agent, adding a second agent or referral for epilepsy surgery evaluation. When adding a second agent keep in mind the drug interactions that can occur
- Headache: If not effective in 2 months, consider stopping or using another agent
Lamotrigine
Best Augmenting Combos for Partial Response or Treatment-Resistance
- Epilepsy: drug interactions complicate multi-drug therapy. Increase dose if using with enzyme-inducing drugs and lower when using with valproate. May be particularly effective in combination with valproate
- Headache: consider beta-blockers, antidepressants, natural products, other AEDs, and non-medication treatments such as biofeedback to improve headache control
Lamotrigine
Tests
- No regular blood tests are recommended
Adverse Effects (AEs)
Lamotrigine
How Drug Causes AEs
- CNS AEs are probably caused by sodium channel blockade effects
Lamotrigine
Notable AEs
- Rash (usually benign) in about 10%
- Sedation, diplopia, ataxia, headache, tremor, insomnia
- Nausea, vomiting, abdominal pain, constipation
- In children, pharyngitis associated with flu syndrome
Lamotrigine
Life-Threatening or Dangerous AEs
Lamotrigine
Weight Gain
- Unusual
Lamotrigine
Sedation
- Unusual
Lamotrigine
What to Do About AEs
- A small dose decrease may improve CNS AEs
- Rashes much more common with rapid dose increases, coadministration with valproic acid and in first 2–8 weeks after beginning therapy
- For mild rashes (non-tender, spotty, and non-confluent, peaks within a few days and improves by 2–3 weeks with no systemic features), evaluate and monitor closely. Stop drug or lower, do not increase dose. If rash does not worsen or quickly improves then can restart with slower titration
- For severe dermatologic reactions with systemic features or involvement of the eyes or mouth, stop the drug and investigate for any organ involvement (renal, hepatic, or hematologic). May require hospitalization
Lamotrigine
Best Augmenting Agents for AEs
- Topical corticosteroids or antihistamines for rash
- Initially dose at night to avoid sedation
