Related Experiment Video
Updated: May 24, 2025
Individualized rTMS Treatment for Depression using an fMRI-Based Targeting Method
Published on: August 2, 2021
Prospective Validation of a Nomogram for Determining the Optimal Dose of Lamotrigine for Augmentation Therapy in
Takeshi Suzuki1, Goyo Nagai2, Kazuo Mihara2,3
1Departments of Hospital Pharmacy, Graduate School of Medicine, University of the Ryukyus, Nishihara, Okinawa, Japan.
Background:
Previous research has shown that a plasma lamotrigine concentration of 12.7 µmol/L may be a threshold for a good therapeutic response to lamotrigine augmentation therapy in Japanese patients with treatment-resistant depression. The optimal dose of lamotrigine can be predicted using a previously established nomogram based on the plasma lamotrigine concentration at week 2. The aim of the present study was to prospectively evaluate the validity of this nomogram.
Methods:
Participants included 59 patients with depression who showed insufficient therapeutic responses to psychotropics, including antidepressants, antipsychotics, and mood stabilizers. The patients were diagnosed with major depressive disorder (n = 26), bipolar II disorder (n = 25), or bipolar I disorder (n = 8). Lamotrigine was administered to all the patients. The initial dose of lamotrigine was 25 mg/d for 32 patients not taking valproate and 25 mg/d every other day for 27 patients taking valproate. Blood samples were collected at week 2 and at least 2 weeks after the final daily dose, which was estimated by a nomogram based on the plasma lamotrigine concentration at week 2. The plasma concentrations of lamotrigine were measured by liquid chromatography-mass spectrometry.
Results:
In 30 of the 32 patients (93.8%) who were not taking valproate and 23 of the 27 patients (85.2%) who were taking valproate, a plasma lamotrigine concentration of 12.7 mcg/mL or higher was achieved at the final daily administration of lamotrigine.
Conclusions:
The results of the present study suggest that the previously established nomogram is valid for determining the optimal dose of lamotrigine for Japanese patients with treatment-resistant depression in clinical settings.
