SYNTHROID® (levothyroxine sodium) tablets, for oral use is a prescription, man-made thyroid hormone that is used to treat a condition called hypothyroidism in adults and children, including infants. Synthroid is a prescription medicine used to treat the symptoms of hypothyroidism and an enlarged thyroid gland (goiter). Learn about dosage, side effects, drug interactions, warnings, and more. Levothyroxine, also known as L-thyroxine, is a synthetic form of the thyroid hormone thyroxine (T 4). [4][7] It is used to treat thyroid hormone deficiency (hypothyroidism), including a severe form known as myxedema coma. [4] It may also be used to treat and prevent certain types of thyroid tumors. [4] It is not indicated for weight loss. [4] Levothyroxine is taken orally (by mouth) or given. Find patient medical information for Levothyroxine (Levoxyl, Synthroid, Tirosint,and others) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings Learn how to take Synthroid® (levothyroxine sodium tablets, USP) the right way. See Use & Important Safety Information, including BOXED WARNING. Synthroid is an inactive T4 that requires conversion to active T3 in your tissues. If you have inflammation, gut issues, genetics that limit conversion enzymes, or endocrine-disrupting chemical exposure, this conversion fails and you remain hypothyroid despite normal labs. Take Synthroid in the evening on an empty stomach to maximize absorption and serum stability. Morning dosing is faster. Synthroid (levothyroxine) is a brand-name prescription drug that’s used to treat hypothyroidism and suppress TSH. Learn about side effects, dosage, and more. Levothyroxine is a man-made thyroid hormone used to treat an underactive thyroid in adults and children, and to lower TSH levels in certain thyroid cancers. An injectable form is used in adults for myxedema coma. Learn about side effects, interactions, and uses. Synthroid (levothyroxine) treats hypothyroidism (low thyroid hormone) and different types of goiters (enlarged thyroid gland). Includes Synthroid side effects, interactions and indications. Description Levothyroxine is used to treat hypothyroidism, a condition where the thyroid gland does not produce enough thyroid hormone. This medicine is also used to help decrease the size of enlarged thyroid glands (also called a goiter). Levothyroxine is also used together with surgery and radioiodine treatment to treat a type of thyroid cancer called thyroid-dependent well-differentiated.