LETHYROX is a brand name for levothyroxine sodium, a synthetic thyroid hormone used to treat hypothyroidism (underactive thyroid). Levothyroxine is a synthetic form of thyroxine (T4), a hormone naturally produced by the thyroid gland. It works by replacing or supplementing the thyroid hormone that the body normally produces. This helps to restore normal metabolic activity in the body, which can be disrupted when the thyroid is underactive. Indications LETHYROX is typically prescribed for: Primary, secondary, and tertiary hypothyroidism: These are conditions where the thyroid gland does not produce enough thyroid hormone due to issues originating in the thyroid gland itself, the pituitary gland, or the hypothalamus, respectively. Goiter: Enlargement of the thyroid gland. Thyroid cancer: As part of the treatment to suppress tumor growth. Thyroid hormone replacement therapy: After thyroidectomy (surgical removal of the thyroid gland). Dosage and Administration Individualized treatmen...