Propylthiouracil (6-propyl-2-thiouracil) is one of the thiocarbamide compounds. It is a white, crystalline substance that has a bitter taste and is very slightly soluble in water.
Each tablet contains propylthiouracil, 50 mg (293.7, µmol), lactose monohydrate, corn starch, colloidal silicon dioxide, povidone, pregelatinized starch, and magnesium stearate.
Propylthiouracil is an antithyroid drug administered orally. The molecular weight is 170.23. The molecular formula is C7H10N2OS, and the structural formula is as follows:
Propylthiouracil inhibits the synthesis of thyroid hormones and thus is effective in the treatment of hyperthyroidism. The drug does not inactivate existing thyroxine and triiodothyronine that are stored in the thyroid or circulating in the blood nor does it interfere with the effectiveness of thyroid hormones given by mouth or by injection.
Propylthiouracil is readily absorbed from the gastrointestinal tract. It is metabolized rapidly and requires frequent administration. Approximately 35% of the drug is excreted in the urine, in intact and in conjugated forms, within 24 hours.
In laboratory animals, various interventions, including propylthiouracil administration, that continuously suppress thyroid function and thereby increase TSH secretion result in thyroid tissue hypertrophy.