Lamotrigine treatment typically produces reductions in brain glutamate levels over a period of approximately three months.
"And the reductions you typically see in, like, three months, for example, on lamotrigine, but we were seeing much larger reductions in six to eight weeks of a ketogenic diet." (said at 1:08:13)
Human magnetic resonance spectroscopy (MRS) studies examining the effect of lamotrigine on brain glutamate levels over 8 to 12 weeks (approximately 2 to 3 months) do not show consistent or typical reductions in overall brain glutamate. In an MRS study of depressed bipolar patients treated with lamotrigine for 10–12 weeks, lamotrigine had no significant overall effect on glutamate/glutamine (Glx) levels in the anterior cingulate cortex, and clinical responders actually exhibited an increase in Glx. Similarly, an 8-week trial in older patients with bipolar depression found no significant changes in glutamate-to-creatine ratios following lamotrigine therapy. While preclinical animal models suggest lamotrigine inhibits presynaptic glutamate release, human in vivo imaging over this timeframe does not demonstrate typical reductions in tissue glutamate concentrations.
- contradicts: Changes in brain Glx in depressed bipolar patients treated with lamotrigine: A proton MRS … (Journal of affective disorders 2019)
"Overall, lamotrigine treatment had no significant effect on Glx levels in ACC. However, in patients who responded clinically to lamotrigine treatment Glx concentrations were significantly increased." (abstract, results, passage verified)
pubmedfull study (doi) - contradicts: Lamotrigine Therapy and Biomarkers of Cerebral Energy Metabolism in Older Age Bipolar Depr… (The American journal of geriatric psychiatry : official journal of the American Association for Geriatric Psychiatry 2019)
"However, there were no associations between NAA/Cr, Glu/Cr, or Gln/Cr and either depression severity or lamotrigine treatment." (abstract, results, passage verified)
pubmedfull study (doi)