0Levothyroxine is also known as: Eltroxin, Euthyrox, Eutroxsig, Evotrox, L Thyroxine Roche, Levo-T, Levotabs, Levotec, Levothroid, Levothyrox, Levoxyl, Novothyrox, Oroxine, Synthroid, Thyquidity, Tirosint, Tirosint-Sol, Unithroid Levothyroxine, also known as L-thyroxine, is a manufactured form of the thyroid hormone thyroxine. It is used to treat thyroid hormone deficiency, including Hashimoto's disease and a severe form known as myxedema coma. It may also be used to treat and prevent certain types of thyroid tumors. Levothyroxine is used to treat an underactive thyroid gland (hypothyroidism). It replaces or provides more thyroid hormone, which is normally produced by the thyroid gland. Low thyroid hormone levels can occur naturally or when the thyroid gland is injured by radiation/medications or removed by surgery. Having enough thyroid hormone is important for normal mental and physical activity. In children, having enough thyroid hormone is important for normal mental and physical development. This medication is also used to treat other types of thyroid disorders (such as certain types of goiters, thyroid cancer). This medication should not be used to treat infertility unless it is caused by low thyroid hormone levels.