CLINICAL PHARMACOLOGY
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displayName: CLINICAL PHARMACOLOGY SECTION
FDA Article Code: 34090-1
The steps in the synthesis of the thyroid hormones are controlled by thyrotropin (Thyroid Stimulating Hormone, TSH) secreted by the anterior pituitary. This hormone’s secretion is in turn controlled by a feedback mechanism effected by the thyroid hormones themselves and by thyrotropin releasing hormone (TRH), a tripeptide of hypothalamic origin. Endogenous thyroid hormone secretion is suppressed when exogenous thyroid hormones are administered to euthyroid individuals in excess of the normal gland’s secretion. 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. The normal thyroid gland contains approximately 200 mcg of levothyroxine (T4) per gram of gland, and 15 mcg of liothyronine (T3) per gram. The ratio of these two hormones in the circulation does not represent the ratio in the thyroid gland, since about 80 percent of peripheral liothyronine comes from monodeiodination of levothyroxine. Peripheral monodeiodination of levothyroxine at the 5 position (inner ring) also results in the formation of reverse liothyronine (T3), which is calorigenically inactive. Liothyronine (T3) levels are low in the fetus and newborn, in old age, in chronic caloric deprivation, hepatic cirrhosis, renal failure, surgical stress, and chronic illnesses representing what has been called the “T3 thyronine syndrome.”
INDICATIONS AND USAGE
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displayName: INDICATIONS & USAGE SECTION
FDA Article Code: 34067-9
Levothyroxine and Liothyronine tablets (thyroid tablets, USP) are indicated: 1. 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). 2. As pituitary TSH suppressants, in the treatment or prevention of various types of euthyroid goiters, including thyroid nodules, subacute or chronic lymphocytic thyroiditis (Hashimoto’s), multinodular goiter, and in the management of thyroid cancer. 3. As diagnostic agents in suppression tests to differentiate suspected mild hyperthyroidism or thyroid gland autonomy.
CONTRAINDICATIONS
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displayName: CONTRAINDICATIONS SECTION
FDA Article Code: 34070-3
Thyroid hormone preparations are generally contraindicated in patients with diagnosed but as yet uncorrected adrenal cortical insufficiency, untreated thyrotoxicosis, and apparent hypersensitivity to any of their active or extraneous constituents. There is no well documented evidence from the literature, however, of true allergic or idiosyncratic reactions to thyroid hormone.
ADVERSE REACTIONS
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displayName: ADVERSE REACTIONS SECTION
FDA Article Code: 34084-4
Adverse reactions other than those indicative of hyperthyroidism because of therapeutic overdosage, either initially or during the maintenance period, are rare (See OVERDOSAGE).
DOSAGE AND ADMINISTRATION
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displayName: DOSAGE & ADMINISTRATION SECTION
FDA Article Code: 34068-7
The dosage of thyroid hormones is determined by the indication and must in every case be individualized according to patient response and laboratory findings. Thyroid hormones are given orally. In acute, emergency conditions, injectable levothyroxine sodium may be given intravenously when oral administration is not feasible or desirable, as in the treatment of myxedema coma, or during total parenteral nutrition. Intramuscular administration is not advisable because of reported poor absorption.
HOW SUPPLIED
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displayName: HOW SUPPLIED SECTION
FDA Article Code: 34069-5
Product: 71335-0671
NDC: 71335-0671-1 60 TABLET in a BOTTLE
NDC: 71335-0671-2 120 TABLET in a BOTTLE
NDC: 71335-0671-3 90 TABLET in a BOTTLE
NDC: 71335-0671-4 30 TABLET in a BOTTLE
NDC: 71335-0671-5 28 TABLET in a BOTTLE
NDC: 71335-0671-6 18 TABLET in a BOTTLE
Product: 71335-0672
NDC: 71335-0672-1 30 TABLET in a BOTTLE
NDC: 71335-0672-2 90 TABLET in a BOTTLE
Thyroid 1 Grain (60mg) Tablet
id: 4e89098e-7e47-43d2-bf84-e752a4c100e1
displayName: PACKAGE LABEL.PRINCIPAL DISPLAY PANEL
FDA Article Code: 51945-4
Thyroid 1/2 grain (30mg) Tablet
id: 2d687ebc-7ab5-4a8a-a381-3781221abe17
displayName: PACKAGE LABEL.PRINCIPAL DISPLAY PANEL
FDA Article Code: 51945-4
