Levothyroxine (generic for Synthroid), also called Euthyrox, Levoxyl, Tirosint, and Unithroid is a prescription drug used to treat chronic thyroid conditions. It is a synthetic version of the human hormone thyroxine (T4). It is a T4 replacement medicine often prescribed to treat hypothyroidism, a condition in which an underactive thyroid gland does not produce enough thyroid hormones to properly regulate your metabolism and weight. Levothyroxine has the same physiological effect as the naturally occurring T4 that is produced by the thyroid gland and it helps maintain normal thyroid hormone levels in the setting of a T4 deficiency. About 80% of the Levothyroxine ingested is absorbed from the digestive tract. The Levothyroxine is then broken down by the liver to the active form of T4. Regular monitoring T4 and TSH levels through lab tests can help determine the effectiveness of the treatment. Liothyronine, the counterpart to Levothyroxine, is a synthetic T3 hormone replacement medicine. Sometimes Liothyronine can be used alone or in combination to treat hypothyroid conditions. Both synthetic hormones (T4 and T3) are found in Armour Thyroid medication.
Levothyroxine prescription can sometimes also be used to treat goiters (enlarged thyroid glands) and even some types of thyroid cancer.
Hypothyroidism can be caused by autoimmune conditions, congenital conditions, injury to the thyroid gland through radiation therapy, radioiodine therapy, or other medications or surgical removal of the thyroid gland.
Symptoms of hypothyroidism can include constipation, weight gain, slow speech, hair loss, lack of energy, excessive tiredness, dry or thick skin, increased sensitivity to cold, muscle aches and joint pain, heavy or irregular menstrual periods and depression. If you are experiencing any of these symptoms, talk to your healthcare provider who can help determine if you need to be treated for hypothyroidism with Levothyroxine, which is the prescription medication of choice in treating thyroid conditions.