Composition, release form and packaging
Tablets – 1 tablet:
- active substance: propylthiouracil – 50.0 mg;
- excipients: lactose monohydrate – 73.9 mg; corn starch – 50.0 mg; colloidal silicon dioxide – 1.5 mg; povidone – 4.0 mg; pregelatinized corn starch – 10.0 mg; magnesium stearate – 0.6 mg.
20 or 100 tablets in a glass bottle.
The bottle along with instructions for use is placed in a cardboard box.
Description of dosage form
White round biconvex tablets with a score line.
Pharmacotherapeutic group
Antithyroid agent.
Pharmacokinetics
Propylthiouracil is well absorbed when administered orally, reaching peak plasma levels 1-2 hours after administration.
Antithyroid drugs are concentrated in the thyroid gland by active transport. Although propylthiouracil may not be detected in the serum 8 hours after administration, the duration of action of a high single dose is 6 to 8 hours due to pronounced accumulation in the thyroid gland.
Oral bioavailability is about 80%.
Pharmacodynamics
Thiouracils act as antithyroid drugs that suppress the intrathyroid peroxidase system. They reduce the process of iodization of thyroglobulin and, accordingly, inhibit the formation of thyroxine. In addition, in thyroglobulin molecules the formation of pair bonds between tyrosyl residues already associated with iodine is disrupted. Propylthiouracil contributes to the depletion of iodine reserves in the thyroid gland. Propylthiouracil inhibits the transformation of thyroxine to triiodothyronine in peripheral tissues.
Indications for use
- Thyrotoxicosis in patients with diffuse toxic goiter or toxic thyroid adenoma;
- preoperative preparation with thyrotoxicosis for resection of the thyroid gland and postoperative therapy;
- preparing patients with thyrotoxicosis for treatment with radioactive iodine.
Contraindications for use
- Severe side effects (agranulocytosis, severe liver dysfunction) with previous treatment with propylthiouracil;
- lactose deficiency, lactose intolerance, glucose-galactose malabsorption;
- hypersensitivity to the drug;
- leukopenia;
- hypothyroidism;
- active hepatitis.
