At a glance
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The Thyroid Axis in Older Individuals With Persistent Subclinical Hypothyroidism: a Mechanistic, Randomized, Double-Blind, Cross-Over Study of Levothyroxine and Liothyronine Administration
In Brief
A clinical study evaluating Levothyroxine, Liothyronine, and 1 other intervention for Subclinical Hypothyroidism. Completed, enrolled 14 participants across 1 site.
Detailed Summary
Subclinical hypothyroidism, defined as an elevated TSH in the setting of normal thyroid hormone levels, is a common diagnosis in the elderly. The purpose of this study is to examine the hypothalamic-pituitary-thyroid axis in men and women aged 70 years and older with persistent subclinical hypothyroidism. To evaluate the mechanism behind this condition, participants will undergo thyrotropin releasing hormone stimulation testing at 3 visits: baseline and while taking two different thyroid hormone preparations, levothyroxine and liothyronine. The investigators will also assess physiologic responses to these two different thyroid hormone medications to help us understand how the thyroid works in advanced age.
Study Details
Timeline
Interventions
Oral levothyroxine with a total starting dose of 0.7mcg/kg/day split into three daily doses will be titrated to a target TSH level of 0.5 -1.5mU/L
Oral liothyronine with a starting dose of 1/3 of the weight-based LT4 dose divided into three daily doses titrated to a target TSH level of 0.5 -1.5mU/L
200 µg intravenous TRH will be given at study visit 1 (baseline), study visit 2 (on first thyroid treatment), and study visit 3 (on second thyroid treatment).