GENERIC NAME: propylthiouracil
BRAND NAME: None available
DRUG CLASS AND MECHANISM: Propylthiouracil (PTU) is an oral medication that is used to manage hyperthyroidism which is due to an overactive thyroid gland. It is an anti-thyroid drug that has a mechanism of action that is similar to methimazole (Tapazole). Graves' disease is the most common cause of hyperthyroidism. It is an autoimmune disease where an individual makes antibodies to thyroid stimulating hormone receptors on cells of the thyroid gland and then trigger overproduction of thyroid hormone by the cells. The two thyroid hormones manufactured by the thyroid gland, thyroxine (T4 ) and triiodothyronine (T3), are formed by combining iodine and a protein called thyroglobulin with the assistance of an enzyme called peroxidase. PTU inhibits iodine and peroxidase from their normal interactions with thyroglobulin to form T4 and T3. This action decreases production of thyroid hormone. PTU also interferes with the conversion of T4 to T3, and, since T3 is more potent than T4, this also reduces the activity of thyroid hormones. The FDA approved PTU in July 1947.
PRESCRIBED FOR: PTU is used to manage hyperthyroidism associated with Graves' disease in patients who did not tolerate methimazole, and are not able to receive surgery or radioactive iodine therapy. It also is used to decrease symptoms of hyperthyroidism in preparation for surgical removal of the thyroid gland or before radioactive iodine therapy in patients who did not tolerated methimazole.
Medically Reviewed by a Doctor on 1/13/2015
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