FDA-Approved Uses for Lamictal
Lamictal (lamotrigine) has two main FDA-approved uses: treating epilepsy and providing maintenance therapy for bipolar I disorder.
Treating Epilepsy and Seizures
For epilepsy, Lamictal can be used in both children and adults. It is approved as an add-on therapy for patients aged 2 years and older experiencing partial-onset, primary generalized tonic-clonic (PGTC), and generalized seizures associated with Lennox-Gastaut syndrome. In adults aged 16 and older with partial-onset seizures, it can be used alone to replace an existing antiepileptic drug.
Maintenance Treatment for Bipolar I Disorder
Lamictal is used for the maintenance treatment of Bipolar I disorder in adults (18 and older) to delay the time between mood episodes. It is not for the acute treatment of manic or mixed episodes.
How Does Lamictal Work? The Mechanism of Action
Lamotrigine's mechanism involves stabilizing the brain's electrical activity. It primarily works by blocking voltage-sensitive sodium channels in neurons, which stabilizes the neuronal membrane and reduces excessive electrical firing. This action also decreases the release of excitatory neurotransmitters like glutamate.
Important Safety Information and Risks
Lamictal has a black box warning about serious skin rashes, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Factors increasing this risk include rapid dose increases, exceeding the starting dose, taking valproate, and being a pediatric patient. Other reported risks include aseptic meningitis, hemophagocytic lymphohistiocytosis (HLH), and suicidal thoughts or behavior.
Off-Label Applications of Lamotrigine
Healthcare providers may prescribe lamotrigine off-label for other conditions. These can include bipolar depression, borderline personality disorder to stabilize mood swings, and as an adjunctive treatment for mood symptoms in schizophrenia and schizoaffective disorder. It has also been used for neuropathic pain like trigeminal neuralgia.
Comparison of Lamictal with Other Mood Stabilizers
| Feature | Lamictal (Lamotrigine) | Lithium | Depakote (Divalproex Sodium) |
|---|---|---|---|
| Drug Class | Triazine Anticonvulsant | Antimanic Agent (Alkali metal ion) | Fatty Acid Derivative Anticonvulsant |
| Primary Mood Use | Maintenance for Bipolar I (better for depression) | Maintenance for Bipolar I (better for mania) | Acute mania and mixed episodes |
| Monitoring | Less frequent monitoring; visual monitoring is important | Requires regular blood tests to check therapeutic levels and assess kidney/thyroid function | Requires regular blood tests to monitor for liver function, platelet counts |
| Serious Rash Risk | Black box warning for serious skin rash (SJS/TEN), especially with rapid titration or valproate use | No significant rash risk associated | Can increase the risk of serious rash when taken with Lamictal |
| Pregnancy Risk | Category C (Risk cannot be ruled out). Discuss risks with doctor. | Category D (Positive evidence of risk). High risk of congenital malformations. | Category X for migraine prevention, Category D for mania/seizures. |
| Common Side Effects | Dizziness, headache, nausea, blurred vision, insomnia, rash | Weight gain, tremor, thirst, nausea, increased urination | Weight gain, hair loss, nausea, stomach pain |
Dosage and Administration Considerations
Starting Lamictal requires slow dose titration to minimize rash risk. The dose is gradually increased over weeks. Concomitant medications can affect lamotrigine levels. Valproate increases levels, requiring lower doses. Carbamazepine and phenytoin decrease levels, requiring higher doses. Estrogen in oral contraceptives can also lower lamotrigine levels.
Common and Serious Side Effects
Common side effects often improve over time and include dizziness, headache, nausea, insomnia, blurred vision, lack of coordination, and rash. Serious side effects requiring immediate medical attention include severe rash (SJS/TEN), fever, swollen glands, signs of aseptic meningitis, jaundice, easy bruising, and mood changes or suicidal thoughts.
Conclusion
Lamictal is primarily used for various seizure types in epilepsy and for preventing mood episodes in Bipolar I disorder. It works by stabilizing neuronal activity through blocking sodium channels. Careful and slow dose titration is essential due to the risk of serious skin rashes and other potential side effects. Under medical guidance, Lamictal is an effective treatment for these chronic conditions.
