Lamotrigine Classification
Lamotrigine (Lamictal) is classified as a mood stabilizer, not an antipsychotic. 1, 2
Pharmacological Classification
- Lamotrigine is a phenyltriazine derivative anticonvulsant that has been repurposed as a mood stabilizer for bipolar disorder 2
- The American Academy of Child and Adolescent Psychiatry recognizes lamotrigine as an approved maintenance therapy option for bipolar disorder, specifically targeting mood stabilization rather than psychotic symptoms 1
- Lamotrigine received FDA approval in 1994 for maintenance treatment of adults with bipolar disorder, establishing its role as a mood stabilizer 3
Mechanism of Action Distinguishes It from Antipsychotics
- Lamotrigine works by inhibiting voltage-sensitive sodium and calcium channels in presynaptic neurons, leading to stabilization of the neuronal membrane and subsequent inhibition of glutamate and aspartate release 2, 3
- This mechanism differs fundamentally from antipsychotics, which primarily block dopamine D2 receptors 2
- The antiglutamatergic and neuroprotective actions are the primary candidate mechanisms for lamotrigine's mood-stabilizing effects, not dopamine antagonism 4
Clinical Profile as a Mood Stabilizer
- Lamotrigine "stabilizes mood from below," meaning it maximally impacts depressive symptoms in bipolar disorder without causing switches to mania or episode acceleration 5
- The American Academy of Child and Adolescent Psychiatry recommends lamotrigine as maintenance therapy in adults with bipolar I disorder, significantly delaying time to intervention for any mood episode compared to placebo 1
- Lamotrigine is particularly effective for preventing depressive episodes in bipolar disorder, which distinguishes it from traditional antimanic agents 1, 5
What Lamotrigine Does NOT Do (Unlike Antipsychotics)
- Lamotrigine has not demonstrated efficacy in the treatment of acute mania, a key distinction from antipsychotics which are first-line for acute manic episodes 1, 2
- Lamotrigine does not have antipsychotic properties and should not be used to treat psychotic symptoms 2
- Unlike antipsychotics, lamotrigine does not cause weight gain, metabolic syndrome, or require monitoring for extrapyramidal symptoms 2
Clinical Use Algorithm
- For acute mania or mixed episodes: The American Academy of Child and Adolescent Psychiatry recommends lithium, valproate, or atypical antipsychotics (aripiprazole, olanzapine, risperidone, quetiapine, ziprasidone)—not lamotrigine 1
- For maintenance therapy: Lamotrigine is recommended as a mood stabilizer, particularly for patients with predominant depressive episodes 1, 2
- For bipolar depression: Lamotrigine shows efficacy in acute treatment and prevention, functioning as a mood stabilizer rather than requiring antipsychotic augmentation 2, 6
Important Safety Distinction
- The critical safety requirement for lamotrigine is slow titration over 6 weeks to minimize risk of Stevens-Johnson syndrome and serious rash (0.1% incidence), which is unrelated to antipsychotic side effects 1, 2
- If lamotrigine is discontinued for more than 5 days, restart with the full titration schedule rather than resuming the previous dose 1