Потенциирование трийодтиронином при недостаточном ответе на терапию ТЦА

"The exact mechanism of action of T3 augmentation remains largely unknown. In depressed patients, the circulating plasma levels of free T4 appear to be normal,
but levels of free T3 may be decreased. Approximately one third of depressed patients show blunting of the TSH response to thyrotropin releasing hormone.
Approximately 15% of depressed patients have elevated basal TSH levels, probably indicating subclinical hypothyroidism, and thyroid autoantibodies
are found in a similar percentage of patients.11
Thyroid abnormalities are found at a higher frequency among TCA nonresponders and this may link with the underlying mechanism of T3 augmentation.In most case reports, patients had normal thyroid function, as in our second case. There seems to be no
relationship between thyroid state and the efficacy of T3 augmentation. In the first case, the patient had sick euthyroid syndrome, which is sometimes seen in
depressed patients. In this condition, peripheral deiodination of T4 to T3 is reduced, although the TSH level is normal.
One proposed mechanism of T3 augmentation is that T3 may raise peripheral thyroid hormone concentrations in patients with covert or borderline hypothyroidism. Other authorities believe that there is no difference in the thyroid state of the
responders and nonresponders to T3 augmentation. 12 L-triiodothyronine may act in euthyroid patients through augmentation of the β-adrenergic system.13 Alternatively, T3 may also affect thyroid utilisation and local neuronal deiodination in the brain."

"The usual dose of T3 in augmentation therapy is 25 µg/d to 50 µg/d. A starting dose of 20 µg increasing to 40 µg was given to the patients in this study. Initial improvement in mood is usually apparent within several days. Goodwin et al reported that there was improvement in all aspects of the depressive syndrome within 1 to 3 days. For the two patients in this study,initial responses were noted after 3 and 7 days. An adequate trial of T3 augmentation should last for 7 to 14 days to reach its full effect. If T3 augmentation is effective, most studies recommend a maintenance
period of 2 months before gradually reducing the dose at the rate of 10 µg every 3 to 7 days."

Triiodothyronine augmentation for the treatment of depression in substance misusers unresponsive to tricyclic antidepressants.