Index of drugs

Hyperthyroidism, including Graves' disease and autonomous toxic thyroid gland adenoma. Preparation for excision of the thyroid gland or radioactive Iodine treatment (¹³¹I) in the case of hyperthyroidism. Thyroid gland.

1 tabl contains 50 mg propylthiouracil.

Thiouracil derivative with thyrostatic (antithyroid) activity. It inhibits the biosynthesis of thyroid hormones (triiodothyronine - T3 and thyroxine - T4) by inhibiting peroxidase activity, preventing the incorporation of iodine into thyroglobulin tyrosyl residues and the joining of iodinated tyrosine derivatives. It also inhibits peripheral dehydrogenation (deionation) of T4 to T3, thus acknowledging propylthiouracil as the drug of choice in very severe cases of hyperthyroidism, especially at the thyroid crisis. After oral administration, propylthiouracil is rapidly absorbed from the gastrointestinal tract, bioavailability is about 80%. The maximum effect occurs after 20-30 minutes after administration. T_0,5 in the blood plasma is relatively short (T._0,5 α to 7-7.5 min, T_0,5 β about 70-75 min, but according to some data it is 240 min). T_0,5 it is prolonged in significant renal failure (up to about 8.5 hours) and in hypothyroidism (8-8.6 hours). It binds to plasma proteins in about 75-80%. The volume of distribution is 0.2-0.4 dm³/ kg body It is metabolized in the liver. Excreted in the urine mainly in the form of glucuronide and in approx. 10% in the unchanged form. The antithyroid effect is not correlated with the serum concentration (it depends on the concentrations obtained in the thyroid gland).

Hypersensitivity to thiouracil derivatives or to any of the excipients. Overactivity with retrosternal goiter, especially when coexisting with thyroid pressure. Liver failure. Haematological disorders (agranulocytosis, leukopenia, anemia).

Due to the risk of agranulocytosis, the blood picture should be regularly monitored during treatment with propylthiouracil with particular attention to the white blood cell pattern. Patients should be advised to report any instances of malaise, sore throat or fever - in each case, a blood test should be performed. Special care should be taken by people previously treated with any of the thioamides who have had side effects in the past. Exercise caution in patients being prepared for surgery; those receiving anticoagulants from the coumarin derivative group; with renal insufficiency (dosage modification indicated); with liver problems. For treatment with¹³¹And, propylthiouracil is used before iodine (it should be discontinued prior to administration of radioactive iodine) and after its administration to prevent possible transient increase of thyrotoxicosis and to accelerate euthyreosis. If an increase in liver enzymes occurs during treatment with propylthiouracil, the preparation should be discontinued immediately.

Propylthiouracil is the drug of choice in pregnant women with hyperthyroidism, in which the use of radioactive iodine is clearly contraindicated, and the use of thiamazole - due to its much greater penetration through the placenta - relatively contraindicated, and in which they can not (eg due to lack of consent ) to subtotal thyroid removal. The levels of propylthiouracil in the fetal circulation are very small compared to those in the mother's blood. In pregnant women, the lowest effective doses of propylthiouracil should be used to ensure euthyroidism or even to allow slight (mild) hyperactivity. Newborns should be carefully examined for thyroid dysfunction (hypothyroidism, less hyperthyroidism). Infants born to mothers treated with propylthiouracil may have hypothyroxinemia (reduced levels of free T4 fraction in the blood) and increased levels of TSH in the blood; these parameters are rapidly normalized during breastfeeding. Propylthiouracil is the drug of choice in the thyrotoxicosis of breast-feeding women. The drug penetrates to breast milk to a small extent.The development of the newborn and thyroid function should be carefully monitored due to the possibility of hypothyroidism in the newborn. The lowest effective doses of propylthiouracil should be used.

Agranulocytosis usually occurs in the initial period of treatment (1-3 months), but it can also occur later. There have also been reports of agranulocytosis in patients re-treated with propylthiouracil who did not develop this symptom for the first time. Agranulocytosis may occur suddenly, with no prodromal symptoms. Periodic examinations of the white blood cell image are essential. Agranulocytosis subsides when the drug is discontinued, and the use of filgrastim (G-CSF) accelerates the normalization of the white blood cell image. There have been reports of vasculitis associated with the presence of neutrophil cytoplasmic antibodies (ANCA).

Orally.Adults: the starting dose is 300 mg in 3 divided doses (100 mg every 8 hours). In patients with severe hyperthyroidism and / or significant hypertrophy of the thyroid gland, the dose is 400 mg / day in divided doses. After obtaining euthyroid (usually after 6-8 weeks of treatment) the dose should be reduced by¹/₃ or¹/₂ at weekly intervals, up to a maintenance dose of 100-150 mg per day. The treatment is usually continued for 1-2 years, although in some patients the definite normalization of thyroid function occurs after 3 months.Thyroid gland: Propylthiouracil is administered to adults at doses of 200-300 mg every 6 h until acute (usually 6 doses). In some patients, due to the inability to take the medicine by mouth, it must be administered by nasal injection or rectal ingots. Due to the lack of dosage forms suitable for this purpose, oily solutions or aqueous solutions with sodium phosphate are prepared extemporaneously from crushed tablets.Children and youth. In children from 6 to 10 years of age, the starting dose is 5-7 mg / kg. (50-150 mg / day) and is given in 3 divided doses every 8 hours. In children> 10 years, the starting dose is also 5-7 mg / kg. (150-300 mg / day) and is given in 3 divided doses every 8 hours. The maintenance doses used in children are¹/₃ down²/₃ the initial dose and are given in one (50 mg) or two (2 times 50 mg) doses. The safety and efficacy of the preparation in children <6 years has not been established.Special groups of patients. Patients with impaired renal function: GFR> 50 ml / min: no dosage adjustment; GFR 10- 50 ml / min: the dose should be reduced by¹/₄; GFR <10 ml / min: the dose should be reduced to half. Only a small part of the drug (approximately 5%) is removed during hemodialysis. At constant dosing (e.g., 200 mg / day), blood levels are maintained in persons undergoing dialysis in the range of therapeutic concentrations, although a slight reduction in dialysis clearance may be expected.Way of giving: the drug should be taken during meals.