Paper
Metabolic effects of liothyronine therapy in hypothyroidism: a randomized, double-blind, crossover trial of liothyronine versus levothyroxine.
Published Aug 24, 2011 · F. Celi, M. Zemskova, J. Linderman
The Journal of clinical endocrinology and metabolism
117
Citations
7
Influential Citations
Abstract
CONTEXT Levothyroxine (L-T(4)) therapy is based on the assumption that the conversion of T(4) into T(3) provides adequate amounts of active hormone at target tissues. However, in rodents, L-T(4) alone does not restore a euthyroid state in all tissues. Previous combination L-T(4)/liothyronine (L-T(3)) therapy trials focused on quality-of-life endpoints, and limited information is available on the effects on other measures of thyroid hormone action. OBJECTIVE Our objective was to evaluate the efficacy of thyroid hormone replacement with L-T(4) or L-T(3) at doses producing equivalent normalization of TSH. PARTICIPANTS, DESIGN, AND SETTING Fourteen hypothyroid patients participated in this randomized, double-blind, crossover intervention at the National Institutes of Health Clinical Center. INTERVENTIONS L-T(3) or L-T(4) were administered thrice daily to achieve a target TSH from 0.5-1.5 mU/liter. Volunteers were studied as inpatients after 6 wk on a stable dose and at the target TSH. MAIN OUTCOME MEASURES Serum thyroid hormones, lipid parameters, and indices of glucose metabolism were evaluated. RESULTS No difference was observed in TSH between L-T(3) and L-T(4) treatments. L-T(3) resulted in significant weight loss [L-T(4), 70.6 ± 12.5, vs. L-T(3), 68.5 ± 11.9 kg (P = 0.009)] and in a 10.9 ± 10.0% decrease in total cholesterol (P = 0.002), 13.3 ± 12.1% decrease in low-density lipoprotein-cholesterol (P = 0.002), and an 18.3 ± 28.6% decrease in apolipoprotein B (P = 0.018). No significant differences were observed in high-density lipoprotein-cholesterol, heart rate, blood pressure, exercise tolerance, or insulin sensitivity. CONCLUSIONS The substitution of L-T(3) for L-T(4) at equivalent doses (relative to the pituitary) reduced body weight and resulted in greater thyroid hormone action on the lipid metabolism, without detected differences in cardiovascular function or insulin sensitivity.
RCT
Very Rigorous Journal
Highly CitedSubstituting L-T(3) for L-T(4) at equivalent doses in hypothyroid patients led to significant weight loss and improved lipid metabolism without affecting cardiovascular function or insulin sensitivity.
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