Thiamazol en methimazol zijn synoniemen van elkaar, en bestaan niet als grondstof in het Fagron assortiment. Thiamazol is wel verkrijgbaar als specialiteit (Strumazol®).
Thiamazol behoort tot de thyreostatica, net als propylthiouracil, en worden voor gelijkaardige toepassing gebruikt. Propylthiouracil is als grondstof beschikbaar bij Fagron.
De beslissing om thiamazol eventueel te vervangen door propylthiouracil, dient te worden genomen door een arts.
Hieronder het gebruik van beide activa beschreven volgens Martindale:
“Thiamazole is a thiourea antithyroid drug that acts by blocking the production of thyroid hormones (see p.2165). It is used in the management of hyperthyroidism (p.2165), including the treatment of Graves’ disease, the preparation of hyperthyroid patients for thyroidectomy, use as an adjunct to radio-iodine therapy, and the treatment of thyroid storm.
Thiamazole is given orally usually in an initial dosage of 15 to 60 mg daily. It is usually given in three divided doses but a single daily dose is also possible. Improvement is usually seen in 1 to 3 weeks and control of symptoms in 1 to 2 months. When the patient is euthyroid the dose is gradually reduced to a maintenance dose, usually 5 to 15 mg daily. Alternatively, the dose may be continued at the initial level with supplemental levothyroxine as a blocking-replacement regimen. Either form of maintenance treatment is usually continued for 1 to 2 years. The initial dose for children is 400 micrograms/kg daily in 3 divided doses; for maintenance this dose may be halved.
Thiamazole doses of 80 to 240 mg daily, usually in 3 or 4 divided doses, have been given intravenously in the management of thyroid storm”
“Propylthiouracil is a thiourea antithyroid drug that acts by blocking the production of thyroid hormones (see p.2165); it also inhibits the peripheral deiodination of thyroxine to tri-iodothyronine. It is used in the management of hyperthyroidism (p.2165), including the treatment of Graves’ disease, preparation of hyperthyroid patients for thyroidectomy, use as an adjunct to radioiodine therapy, and the treatment of thyroid storm.
Propylthiouracil is usually given orally. Initial doses range from 150 to 450 mg daily (the BNF recommends 200 to 400 mg daily), although in severe cases initial doses of 600 to 1200 mg daily have been used. It has often been given in divided daily doses but once daily dosage is also possible. Improvement is usually seen in 1 to 3 weeks and control of symptoms is achieved in 1 to 2 months. When the patient is euthyroid the dose is gradually reduced to a maintenance dose, usually 50 to 150 mg daily. Treatment is usually continued for 1 to 2 years. In the UK, the BNFC recommends the following initial doses by mouth for children:
• in neonates: 2.5 to 5 mg/kg twice daily
• in those aged 1 month to 1 year: 2.5 mg/kg three times daily
• in those aged 1 to 5 years: 25 mg three times daily
• in those aged 5 to 12 years: 50 mg three times daily
• in those aged 12 to 18 years: 100 mg three times daily
These doses are given until the patient is euthyroid and then adjusted as needed; higher doses may be required, especially in thyrotoxic crises.
Doses should be reduced in renal impairment (below).
Doses may also need to be reduced in hepatic impairment”
