Should a patient with a history of psychiatric illness, who has responded to an SSRI increase and shown no difference with a Lamotrigine reduction from 200mg to 100mg, taper off Lamotrigine?

Should Lamotrigine Be Tapered Off?

Yes, the provider should continue tapering and discontinue lamotrigine in this patient who has responded to SSRI optimization and experienced no clinical change when lamotrigine was reduced from 200mg to 100mg.

Rationale for Discontinuation

The clinical scenario demonstrates two key findings that support discontinuation:

• The patient responded to SSRI dose increase, indicating the SSRI is providing therapeutic benefit 1
• No clinical deterioration occurred when lamotrigine was reduced by 50% (from 200mg to 100mg), suggesting lamotrigine is not contributing meaningfully to symptom control

Evidence Supporting This Decision

Lamotrigine's Role in Psychiatric Treatment

Lamotrigine has established efficacy primarily for:

• Bipolar depression as monotherapy or maintenance therapy 2, 3
• Augmentation in treatment-resistant unipolar depression when SSRIs alone are insufficient 4

However, when an SSRI provides adequate response, continuing lamotrigine adds unnecessary polypharmacy without demonstrated benefit 4.

The Successful Dose Reduction Test

The patient's lack of symptom change during the 200mg to 100mg taper serves as a naturalistic trial demonstrating lamotrigine is not essential for current stability 3. This clinical observation is more relevant than theoretical concerns about medication withdrawal.

Safety Considerations for Discontinuation

Lamotrigine can be safely discontinued with appropriate tapering 3:

• Gradual dose reduction minimizes withdrawal effects
• No significant withdrawal syndrome is associated with lamotrigine discontinuation (unlike SSRIs) 1
• Abrupt discontinuation should be avoided, but controlled tapering is well-tolerated 5, 3

Recommended Tapering Approach

Continue the taper from 100mg:

• Reduce by 25-50mg every 1-2 weeks 3
• Monitor for mood destabilization during taper
• Complete discontinuation is appropriate if no symptoms emerge

Monitor during taper for:

• Return of depressive symptoms
• Mood instability or affective switches 6
• Changes in anxiety or sleep patterns 1

Common Pitfalls to Avoid

Do not maintain unnecessary polypharmacy simply because the patient is stable. The successful dose reduction already demonstrates lamotrigine is not required 4, 3.

Do not taper too rapidly. While lamotrigine lacks a significant discontinuation syndrome, gradual reduction over several weeks allows proper monitoring 5, 3.

Do not assume all medications contributing to past stability must be continued indefinitely. Clinical reassessment through careful tapering is appropriate when one agent (the SSRI) provides clear benefit 1.

If Symptoms Re-emerge

Should depressive symptoms return during or after lamotrigine discontinuation:

• First optimize the SSRI dose to maximum therapeutic levels 1
• Consider reinstating lamotrigine only if SSRI optimization fails 4
• Evaluate for other augmentation strategies if needed 1