Thyrolar Tablets (Liotrix Tablets, USP) contain triiodothyronine (T3 liothyronine) sodium and tetraiodothyronine (T4 levothyroxine) sodium in the amounts listed in the “How Supplied” section. (T3 liothyronine sodium is approximately four times as potent as T4 thyroxine on a microgram for microgram basis.
Thyrolar Tablets are indicated:
- As replacement or supplemental therapy in patients with hypothyroidism of any etiology, except transient hypothyroidism during the recovery phase of subacute thyroiditis. This category includes cretinism, myxedema, and ordinary hypothyroidism in patients of any age (children, adults, the elderly), or state (including pregnancy); primary hypothyroidism resulting from functional deficiency, primary atrophy, partial or total absence of thyroid gland, or the effects of surgery, radiation, or drugs, with or without the presence of goiter; and secondary (pituitary), or tertiary (hypothalamic) hypothyroidism (See WARNINGS).
- As pituitary TSH suppressants, in the treatment or prevention of various types of euthyroid goiters, including thyroid nodules, sub-acute or chronic Iymphocytic thyroiditis (Hashimoto's), multinodular goiter, and in the management of thyroid cancer.
- As diagnostic agents in suppression tests to differentiate suspected mild hyperthyroidism or thyroid gland autonomy.
Published Studies Related to Thyrolar (Liothyronine / Levothyroxine)
Metabolic effects of liothyronine therapy in hypothyroidism: a randomized,
double-blind, crossover trial of liothyronine versus levothyroxine. 
CONCLUSIONS: The substitution of L-T(3) for L-T(4) at equivalent doses (relative
The pharmacodynamic equivalence of levothyroxine and liothyronine: a randomized, double blind, cross-over study in thyroidectomized patients. [2010.05]
CONTEXT: The substitution of liothyronine (L-T3) for levothyroxine (L-T4) is commonly employed during thyroid hormone (TH) withdrawal in preparation for diagnostic and therapeutic interventions on thyroid cancer patients. Presently, only limited data are available on the L-T3 for L-T4 therapeutic substitution. Objective To characterize the pharmcodynamic equivalence of L-T3 and L-T4... CONCLUSIONS: This is the first study addressing the equivalency between L-T3 and L-T4 therapy measured by baseline and TRH-stimulated TSH. The therapeutic substitution of L-T3 for L-T4 was achieved at approximately 1:3 ratio.
The pharmacodynamic equivalence of levothyroxine and liothyronine: a randomized,
double blind, cross-over study in thyroidectomized patients. 
Objective To characterize the pharmcodynamic equivalence of L-T3 and L-T4... CONCLUSIONS: This is the first study addressing the equivalency between L-T3 and
Efficacy of combined levothyroxine and liothyronine as compared with levothyroxine monotherapy in primary hypothyroidism: a randomized controlled trial. 
OBJECTIVES: To examine the efficacy of combination therapy with levothyroxine and liothyronine in improvement of general health, psychological problems, and metabolic status in primary hypothyroidism... CONCLUSIONS: The data do not support the hypothesis that combined therapy improves the well-being and general health of patients.
Combined treatment with sertraline and liothyronine in major depression: a randomized, double-blind, placebo-controlled trial. [2007.06]
BACKGROUND: Antidepressant treatments that achieve a higher remission rate than those currently available are urgently needed. The thyroid hormone triiodothyronine may potentiate antidepressant effects. OBJECTIVE: To determine the antidepressant efficacy and safety of liothyronine sodium (triiodothyronine) when administered concurrently with the selective serotonin reuptake inhibitor sertraline hydrochloride to patients with major depressive disorder... CONCLUSIONS: These results demonstrate enhancement of the antidepressant effect of sertraline by concurrent treatment with liothyronine without a significant increase in adverse effects. The antidepressant effect of liothyronine may be directly linked to thyroid function.
Page last updated: 2013-02-10