Liothyronine sodium

Sodium Liothyronine. Sodium hothyroniae [55-06-1] is the sodium salt of L-3,5,3 -triiodothyroniQe. It is made by the controlled iodiaation of L-3,5-diiodothyronine. It may be contaminated by starting material or l-T. The USP assay (49) describes a chromatographic separation specifying 3,5-T2... 

Liothyronine sodium (Cytomel) is the sodium salt of the naturally occurring levorotatory isomer of T3. Liothyronine is generally not used for maintenance thyroid hormone replacement therapy because of its short plasma half-life and duration of action. The use of T3 alone is recommended only in special situations, such as in the initial therapy of myxedema and myxedema coma and the short-term suppression of TSH in patients undergoing surgery for thyroid cancer. The use of T3 alone may also be useful in patients with the rare condition of 5 -deiodinase deficiency who cannot convert T4 to T3. 

Liotrix (Euthroid, Thywlar) is a 4 1 mixture of levothyroxine sodium and liothyronine sodium. Like levothyroxine, liotrix is used for thyroid hormone replacement therapy in hypothyroid patients. Although the idea of combining T4 and T3 in replacement therapy so as to mimic the normal ratio secreted by the thyroid gland is not new, it does not appear that liotrix offers any therapeutic advantage over levothyroxine alone. 

Thyroid hormones levothyroxine sodium liothyronine sodium thyroid... 

Ultraviolet Spectrum. Liothyronine sodium aqueous alkali— 319 nm (Al =65 a). 

Betamethasone Sodium 570.8 Bunamidine Hydroxy- 673.0 Liothyronine Sodium... 

Liothyronine Sodium, USP. Lioihyroninc sodium. O-(4-hydroxy-3-iodophenyl)-3.5-dii )do-i.-lhyroxine monoso-dium. salt (Cylomel), is the sodium salt of L-3.3. S-triiodolhy-ronine. It occurs as a light-tan. odorless, crystalline powder, which is slightly soluble in water or alcohol and has a specific rotation of -H 18 to 22° in a mixture of diluted HCI and alcohol. 

Liothyronine sodium occurs in vivo together with levo-ihyroxinc sodium it has the same qualitative activities as thyroxine but is more active. It is absorbed readily from the gastrointestinal tract, is cleared rapidly from the bloodstream, and is hound more loosely to plasma proteins than is thyroxine, probably because of the less acidic phenolic hydroxyl group. 

Liotrix (Euthyroid, Thyrolar) A mixture of levothyroxine sodium and liothyronine sodium... 

Hypothyroid is treated by administering levothyroxine sodium (increases thyroxine and triiodothyronine for long-term treatment), Liothyronine (increases triiodothyronine for short-term treatment), Liotrix (a mixture of levothyroxine sodium and liothyronine sodium), thyroid (seldom used), or thyroglobulin (seldom used). 

Liothyronine sodium is a thyroid hormone that increases metabolic rate of body tissues and is needed for normal growth and maturation. It is indicated for the replacement or supplemental therapy in hypothyroidism in TSH suppression for treatment or prevention of euthyroid goiters (e.g., thyroid nodules, multinodular goiters, enlargement in chronic thyroiditis) and as a diagnostic agent in suppression tests to differentiate suspected hyperthyroidism from euthyroidism and in treatment of myxedema coma/precoma (IV). 

The synthetic preparations used are the sodium salts of the natural isomers of the thyroid hormones. Levothyroxine sodium (L-T, synthroid, levoxyl, levothroid, unithroid, others) is available in tablets in a variety of doses and as a lyophilized powder for injection. L-T has a narrow therapeutic index, and the FDA has mandated demonstration of bioequivalence for brand and generic preparations by the various producers. Liothyronine sodium (L-Tft is available in tablets (cytomel) and in an injectable form (triostat). A mixture of L-T and L-T is marketed as liotrix (thyroiar). Desiccated thyroid preparations, derived from whole animal thyroids and containing both T and T have highly variable biologic activity and are much less desirable. 

Crystalline T3 (liothyronine sodium, Cytomel) has a rapid onset and short duration of action. It is the therapy of choice when it is desirable to have rapid onset or cessation of activity, such as in patients with heart disease. 

Rapaka, R.S. Knight, P.W. Prasad, V.K. Reversed-phase high-performance liquid chromatographic analysis of liothyronine sodium and levothyroxine sodium in tablet formulations preliminary studies on dissolution and content uniformity. J.Pharm.Sci., 1981, 70, 131-134... 

Liothyronine sodium, Ci5Hu04Nl3Na, Mol. Wt. 673 0, is the sodium salt of L-tri-iodothyronine. It may be assayed by the oxygen-flask combustion method, using about 15 mg and titrating with 0-02N sodium thiosulphate. 1 ml 0-02N — 0 0007478 g. 

Tablets of Liothyronine Sodium, B.P. May be of any strength between 5 and 50 micrograms. These tablets contain too much organic matter in relation to iodine content for application of the flask-combustion method.

Within the thyroid system, disease states can lead to hypothyroidism and hyperthyroidism. Hypothyroidism results from abnormally low production of thyroid hormone in thyroid glands. The prevalence of this condition is reported as being between 2% and 5% of the world population, although a substantial number are in the sub-clinical category. Hypothyroidism is much more common in females than in males, and the frequency of the disease increases with age. The problem may arise due to an insufficient intake of iodine in the diet. It may be due to an inherited disorder (Hashimoto s thyroiditis) or it may be due to inflammation of the thyroid gland (lymphocytic thyroiditis). The conventional treatment for this condition is use of thyroid hormones levothyroxine sodium or liothyronine sodium (Fig. 20.11). 

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