Is lamotrigine (an anticonvulsant mood stabilizer) sufficient as a mood stabilizer to allow the addition of an antidepressant in a patient with bipolar disorder?

From the Guidelines

Lamotrigine can be a sufficient mood stabilizer to allow the addition of an antidepressant in a patient with bipolar disorder, particularly for those with bipolar II or those who experience more depressive episodes than manic ones. When using lamotrigine as a mood stabilizer, it's essential to start at a low dose (25mg daily) and gradually increase (usually by 25mg every 1-2 weeks) to minimize the risk of serious rash, with a target dose of 100-200mg daily for most adults 1.

Key Considerations

• When adding an antidepressant, it's generally safer to use an SSRI like sertraline or fluoxetine rather than a tricyclic or SNRI, which may carry higher risks of triggering mania 1.
• The combination should be closely monitored, especially during the first few months, as antidepressants can potentially trigger manic episodes even with mood stabilizer coverage 1.
• Lamotrigine works differently from other mood stabilizers like lithium or valproate, as it's particularly effective at preventing depressive episodes rather than manic ones 1.
• For patients with frequent or severe manic episodes, lamotrigine alone might not provide adequate protection when adding an antidepressant, and a second mood stabilizer or an atypical antipsychotic might be needed for comprehensive mood coverage 1.

Monitoring and Adjustment

• Clinicians should assess patient status, therapeutic response, and adverse effects of antidepressant therapy on a regular basis beginning within 1 to 2 weeks of initiation of therapy 1.
• Patients should be monitored for the emergence of agitation, irritability, or unusual changes in behavior, because these symptoms can indicate that the depression is getting worse 1.
• The risk for suicide attempts is greater during the first 1 to 2 months of treatment, and close monitoring is advised 1.

From the Research

Efficacy of Lamotrigine as a Mood Stabilizer

• Lamotrigine has been shown to be an effective maintenance therapy for patients with bipolar I disorder, significantly delaying time to intervention for any mood episode 2, 3.
• It has also been found to be effective in delaying time to intervention for a depressive episode, although its efficacy in delaying time to intervention for a manic/hypomanic episode is limited 2, 3.
• Studies have demonstrated that lamotrigine is generally well tolerated, does not appear to cause bodyweight gain, and does not require monitoring of serum levels 2, 3.

Use of Lamotrigine in Combination with Antidepressants

• There is evidence to suggest that lamotrigine can be used as a mood stabilizer to allow the addition of an antidepressant in patients with bipolar disorder 4, 5.
• Lamotrigine has been found to be effective in alleviating depressive symptoms of bipolar disorder without causing mood destabilization or precipitating mania 4.
• A clinical case series study found that 65% of patients with bipolar disorder treated with lamotrigine were rated as very much or much improved, suggesting its potential as a mood stabilizer and antidepressant 5.

Safety and Tolerability of Lamotrigine

• Lamotrigine has been found to be well tolerated in maintenance studies, with common adverse events including headache, nausea, infection, and insomnia 2, 3.
• The incidence of serious rash with lamotrigine treatment is low, at 0.1% in all studies of bipolar disorder 2, 3.
• Lamotrigine has been found to be safe and effective in patients with bipolar spectrum disorders, with 47.1% of patients achieving remission on depression and 32.4% remaining euthymic during follow-up 6.