Methimazole (Thiamazole)
- Atc Codes:H03BB02
- CAS Codes:60-56-0
- PHARMGKB ID:60-56-0
Table of contents
- Brand Names
- Chemistry
- Pharmacologic Category
- Mechanism of Action
- Therapeutic Use
- Pregnancy and Lactation Implications
- Contraindications
- Warnings and Precautions
- Adverse Reactions
- Genes that may be involved
- Inhibits
- Induces
- Drug Interactions
- Dosage
- Pharmacokinetics and Pharmacodynamics
- Special Considerations
Brand Names
Europe
Austria: Thiamazol; Belgium: Strumazol; Bulgaria: Metizol, Thyrozol; Czech Republic: Thyrozol; Denmark: Thycapzol; Estonia: Thyrozol; France: Thyrozol; Germany: Favistan, Methizol, Thiamazol; Greece: Unimazole; Hungary: Metothyrin; Italy: Tapazole; Lithuania: Thiamazole; Luxembourg: Strumazol, Thyrozol; Netherlands: Strumazol; Poland: Metizol, Thiamazole, Thyrozol; Portugal: Metibasol; Romania: Thyrozol; Slovenia: Athyrazol; Spain: Tirodril; Sweden: Thacapzol.
North America
Canada: Methimazole, Tapazole; USA: Methimazole, Tapazole.
Latin America
Argentina: Danantizol; Brazil: Tapazol; Mexico: Tiamazol.
Drug combinations
Chemistry
Methimazole: C~4~H~6~N~2~S. Mw: 114.17. (1) 2H-Imidazole-2-thione, 1,3-dihydro-1-methyl-; (2) 1-Methylimidazole-2-thiol. CAS-60-56-0.
Pharmacologic Category
Antithyroid Agents; Thioamide. (ATC-Code: H03BB02).
Mechanism of action
Inhibits synthesis of thyroid hormones by blocking oxidation of iodine in thyroid gland, blocking ability of iodine to combine with tyrosine to form thyroxine and triiodothyronine.
Therapeutic use
Palliative treatment of hyperthyroidism, to return hyperthyroid patient to normal metabolic state prior to thyroidectomy, and to control thyrotoxic crisis which may accompany thyroidectomy.
Pregnancy and lactiation implications
Adverse events might occur in fetus following maternal use. Thioamides are treatment of choice for hyperthyroidism during pregnancy. Enters breast milk.
Unlabeled use
Contraindications
Hypersensitivity to methimazole or any component of the formulation. Breast-feeding.
Warnings and precautions
Might cause acneiform eruptions. Might cause hypoprothrombinemia and bleeding (use with particular caution in patients >40 years of age). Might cause significant bone marrow depression (agranulocytosis). Aplastic anemia, thrombocytopenia, and leukopenia may also occur. Antithyroid agents associated with rare but severe dermatologic reactions. Rash and urticaria common. Rare, severe hepatic reactions (hepatic necrosis, hepatitis) might occur. Antithyroid agents associated with a variety of autoimmune reactions, including lupus-like syndrome. Antithyroid agents associated (rarely) with development of ANCA-positive vasculitis or leukocytoclastic vasculitis.