《NOVOTHYROX (levothyroxine sodium tablets》.pdf

NOVOTHYROX® (levothyroxine sodium tablets, USP) Rx only DESCRIPTION NOVOTHYROX (levothyroxine sodium tablets, USP) contains synthetic crystalline L-3, 3’, 5, 5’-tetraiodothyronine sodium salt [levothyroxine (T ) 4 sodium]. Synthetic T is identical to that produced in the human thyroid gland. 4 Levothyroxine (T ) sodium has an empirical formula of C H I NNaO • H O, 4 15 10 4 4 2 molecular weight of 798.86 g/mol (anhydrous), and structural formula as shown: I I NH 2 HO O CH C COONa * x H O 2 2 H I I 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. 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 (T ) and L-triiodothyronine (T ), 4 3