Indicated for: hyperthyroidism
Route of administration: oral
Substance: thiamazole (antithyroid agent)
ATC: H03BB02 (Systemic hormonal preparations, excluding sex hormones and insulins | Antithyroid preparations | Sulfur-containing imidazole derivatives)
Thiamazole, also known as methimazole, is a medication used to treat hyperthyroidism, a condition in which the thyroid gland produces excessive amounts of thyroid hormones. It works by inhibiting the synthesis of thyroid hormones, blocking the enzyme thyroid peroxidase, which is essential for the production of thyroxine (T4) and triiodothyronine (T3).
Thiamazole is commonly used in the treatment of Graves' disease, toxic diffuse goiter, and prior to thyroid surgery or radioactive iodine therapy to control thyroid hormone levels. The medication is taken orally, usually once or twice daily, depending on the severity of the condition.
Common side effects include skin rashes, itching, nausea, and joint pain. In rare cases, it can cause agranulocytosis (a severe drop in white blood cells), hepatotoxicity, or pancreatitis. It is contraindicated during the first trimester of pregnancy, as it may affect fetal development, but it can be used with caution in later trimesters. Regular monitoring of thyroid function and blood counts is essential during treatment.