LIOTHYRONINE SODIUM- liothyronine sodium tablet
Paddock Laboratories, Inc.
Drugs with thyroid hormone activity, alone or together with other therapeutic agents, have been used for the treatment of obesity. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects.
DESCRIPTION
Thyroid hormone drugs are natural or synthetic preparations containing tetraiodothyronine (T4 , levothyroxine) sodium or triiodothyronine (T3 , liothyronine) sodium or both. T4 and T3 are produced in the human thyroid gland by the iodination and coupling of the amino acid tyrosine. T4 contains four iodine atoms and is formed by the coupling of two molecules of diiodotyrosine (DIT). T3 contains three atoms of iodine and is formed by the coupling of one molecule of DIT with one molecule of monoiodotyrosine (MIT). Both hormones are stored in the thyroid colloid as thyroglobulin.
Thyroid hormone preparations belong to two categories: (1) natural hormonal preparations derived from animal thyroid, and (2) synthetic preparations. Natural preparations include desiccated thyroid and thyroglobulin. Desiccated thyroid is derived from domesticated animals that are used for food by man (either beef or hog thyroid), and thyroglobulin is derived from thyroid glands of the hog. The United States Pharmacopeia (USP) has standardized the total iodine content of natural preparations. Thyroid USP contains not less than (NLT) 0.17 percent and not more than (NMT) 0.23 percent iodine, and thyroglobulin contains not less than (NLT) 0.7 percent of organically bound iodine. Iodine content is only an indirect indicator of true hormonal biologic activity.
Liothyronine Sodium Tablets, USP contain liothyronine (L-triiodothyronine or LT3 ), a synthetic form of a natural thyroid hormone, and is available as the sodium salt. Twenty-five mcg of liothyronine is equivalent to approximately 1 grain of desiccated thyroid or thyroglobulin and 0.1 mg of L-thyroxine.
Each round, white Liothyronine Sodium Tablet, USP contains liothyronine sodium equivalent to liothyronine as follows: 5 mcg debossed 5 and 220; 25 mcg scored and debossed 25 and 222; 50 mcg scored and debossed 50 and 223. Inactive ingredients consist of calcium sulfate, microcrystalline cellulose, hypromellose, talc, and colloidal silicon dioxide.
CLINICAL PHARMACOLOGY
The mechanisms by which thyroid hormones exert their physiologic action are not well understood. These hormones enhance oxygen consumption by most tissues of the body, 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.
