Thyroid Augmentation May Improve Depression in Women with Treatment-Resistant Bipolar Depression
We have previously written about a study of supra-physiological doses of levothyroxine (a synthetic version of the hormone T4 sold under the brand name Synthroid) performed by Mike Bauer and colleagues in Dresden, Germany and at UCLA. Sixty-three patients were initially treated with an antidepressant and/or a mood stabilizer for one week during a single-blind phase. Then the six-week double-blind phase of the study began, in which patients were given either adjunctive T4 (in the form of levothyroxine ) or placebo, and this was followed by an additional six weeks of open treatment with T4. Patients were started at 100mcg and increased on a weekly basis to 200 and then 300mcg/day.
Overall, T4 had no statistically significant effect that differentiated it from placebo, but among women, there was a significantly greater degree of improvement in the Hamilton Rating Scale for Depression scores for those on T4 (-42.4%) than for those on placebo (-16.6%), p= .018.
Editor’s note: This study is the first randomized, placebo-controlled trial of supra-physiological doses of T4. A small series of reports in the literature from several different investigative groups had previously suggested efficacy of this compound in rapid cycling and treatment-resistant patients. Read more
Thyroid Augmentation Helps Depression (And Bipolar Disorder in Women)
Low dose thyroid replacement treatment with T3 (Cytomel) (25-37.5 µg) is typically recommended for acute antidepressant augmentation in unipolar and bipolar depression. This approach has few side effects and works even in those with normal thyroid function at baseline.
Some data also supports the use of relatively high (supraphysiological) doses of T4 (Synthroid) late in the treatment of highly treatment-resistant patients with unipolar and bipolar disorder. These supra-physiological doses of T4 typically ranged from 300-500 µg/day, producing a free thyroxine index of 150% of normal. This is usually moderately well tolerated, although minor degrees of sweating, tachycardia (fast heartbeat), and other signs of hyperthyroidism can accompany this regimen. If this approach is employed, it is particularly important to increase the dose of T4 (Synthroid) very slowly because of its relatively long half-life—about 12 days. (That is, if a patient takes a high dose of T4 and then stops their medication completely, 12 days later blood levels will only have decreased to half of what they originally were.)
Findings about high-dose T4 for women with treatment-resistant bipolar illness after the jump. Read more
