Drug Groups

approved

Description

The L-triiodothyronine (T3, liothyronine) thyroid hormone is normally synthesized and secreted by the thyroid gland in much smaller quantities than L-tetraiodothyronine (T4, levothyroxine, L-thyroxine). Most T3 is derived from peripheral monodeiodination of T4 at the 5 position of the outer ring of the iodothyronine nucleus. The hormone finally delivered and used by the tissues is mainly T3. [PubChem]

Indication

Used as replacement or supplemental therapy in patients with hypothyroidism of any etiology, except transient hypothyrodism during the recovery phase of subacute thyroiditis.

Pharmacology

Thyroid hormone drugs are natural or synthetic preparations containing T₄ or T₃ or both. T₄ and T₃ are produced in the human thyroid gland by the iodination and coupling of the amino acid tyrosine. Liothyronine (T₃) contains three atoms of iodine and is formed by the coupling of one molecule of diiodotyrosine (DIT) with one molecule of monoiodotyrosine (MIT). These hormones enhance oxygen consumption by most tissues of the body and increase the basal metabolic rate and the metabolism of carbohydrates, lipids and proteins. Thus, they exert a profound influence on every organ system in the body and are of particular importance in the development of the central nervous system.

Affected Organisms

Absorption

95% in 4 hours

Half Life

2.5 days

Protein Binding

99.7%

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