antitiroidienii

Antitiroidienii, known in English as antithyroid drugs, are medications used to reduce the production of thyroid hormones in hyperthyroidism. The principal agents are thionamides, including methimazole (carbimazole is a closely related prodrug) and propylthiouracil (PTU). Methimazole and carbimazole act mainly by inhibiting thyroid peroxidase, blocking iodination and the coupling steps in thyroid hormone synthesis. PTU inhibits thyroid peroxidase as well and, in addition, reduces peripheral conversion of T4 to the more active T3.

Clinical use and indications include Graves disease, toxic multinodular goiter, and toxic adenoma. They are commonly employed to achieve or maintain a euthyroid state, either as initial therapy, as a preparatory step before thyroid ablation or surgery, or in specific settings such as pregnancy, where PTU is often preferred during the first trimester due to concerns about methimazole-associated fetal abnormalities.

Adverse effects range from mild to serious. Common effects include rash and arthralgias. More serious but rarer risks are agranulocytosis, vasculitis, and hepatotoxicity, with PTU carrying a particular risk of severe liver injury and methimazole more commonly associated with cholestatic jaundice. Monitoring typically includes baseline and periodic thyroid function tests, complete blood counts, and liver function tests when using PTU.

Discontinuation or alternative therapy (radioactive iodine or surgery) may be considered if adverse effects occur or if long-term control is required. Regular follow-up and patient education on signs of infection or liver problems are essential.