Novothyrox

Generic name:levothyroxine sodium
Dosage form: tablet
Drug class:Thyroid drugs

Medically reviewed by Drugs.com. Last updated on Mar 22, 2022.

Novothyrox Description

Novothyrox (levothyroxine sodium tablets, USP) contains synthetic crystalline L-3, 3’,5,5’-tetraiodothyronine sodium salt [levothyroxine (T4) sodium]. Synthetic T4 is identical to that produced in the human thyroid gland. Levothyroxine (T4) sodium has an empirical formula of C15H10I4NNaO4 • H2O, molecular weight of 798.86 g/mol (anhydrous), and structural formula as shown:

Inactive Ingredients

Novothyrox (levothyroxine sodium tablets, USP) contain the following inactive ingredients: corn starch, croscarmellose sodium, gelatin, lactose monohydrate, and magnesium stearate. All strengths of Novothyrox tablets are formulated without color additives for patients who are sensitive to dyes.

Novothyrox - Clinical Pharmacology

Thyroid hormone synthesis and secretion is regulated by the hypothalamic-pituitary-thyroid axis. Thyrotropin-releasing hormone (TRH) released from the hypothalamus stimulates secretion of thyrotropin-stimulating hormone, TSH, from the anterior pituitary. TSH, in turn, is the physiologic stimulus for the synthesis and secretion of thyroid hormones, L-thyroxine (T4) and L-triiodothyronine (T3), by the thyroid gland. Circulating serum T3 and T4 levels exert a feedback effect on both TRH and TSH secretion. When serum T3 and T4 levels increase, TRH and TSH secretion decrease. When thyroid hormone levels decrease, TRH and TSH secretion increase.

The mechanisms by which thyroid hormones exert their physiologic actions are not completely understood, but it...