Indication: For the treatment of hyperthyroidism, goiter, Graves disease and psoriasis.
Pharmacology: Used in the treatment of hyperthyroidism or an overactive thyroid gland, Methimazole inhibits the synthesis of thyroid hormones and thus is effective in the treatment of hyperthyroidism. It may also be used to ameliorate hyperthyroidism in preparation for subtotal thyroidectomy or radioactive iodine therapy.
Mechanism Of Action: Methimazole binds to thyroid peroxidase and thereby inhibits the conversion of iodide to iodine. Thyroid peroxidase normally converts iodide to iodine (via hydrogen peroxide as a cofactor) and also catalyzes the incorporation of the resulting iodide molecule onto both the 3 and/or 5 positions of the phenol rings of tyrosines found in thyroglobulin. Thyroglobulin is degraded to produce thyroxine (T4) and tri-iodothyronine (T3), which are the main hormones produced by the thyroid gland. So Methimazole effectively inhibits the production of new thyroid hormones.
Drug Category: Antithyroid Agents; ATC:H03B
Brand Names/Synonyms: Basolan; Danantizol; Favistan; Frentirox; Mercaptazole; Mercasolyl; Mercazole; Mercazolyl; Merkastan; Merkazolil; Metazolo; Methamazole; Methiamazole; Methimazol; Methimazole; Methylmercaptoimidazole; Metizol; Metothyrin; Metothyrine; Metotirin; Propyl-Thyracil; Strumazol; Strumazole; Tapazole; Tapuzole; Thacapzol; Thiamazol; Thiamazole; Thimazole; Thycapsol; Thycapzol; Thymidazol; Thymidazole; Usaf El-30
Dosage Forms: TABLET
Absorption: Rapid, oral bioavailability = 93%
Interactions:
DrugBank: Interactions for Methimazole
Interactions for Methimazole:
Anticoagulants (oral): The activity of oral anticoagulants may be potentiated by
anti-vitamin-K activity attributed to methimazole.
ß-adrenergic blocking agents: Hyperthyroidism may cause an increased clearance of
beta ratio. A dose reduction of beta-adrenergic blockers may be needed when a hyperthyroid patient becomes
euthyroid.
Digitalis glycosides: Serum digitalis levels may be increased when hyperthyroid patients
on a stable digitalis glycoside regimen become euthyroid; reduced dosage of digitalis glycosides may be required.
Theophylline: Theophylline clearance may decrease when hyperthyroid patients on a stable
theophylline regimen become euthyroid; a reduced dose of theophylline may be needed.
Chemical IUPAC Name: 1-methyl-1H-imidazole-2-thiol
Chemical Formula: C4H6N2S
Half Life: 5-6 hours
Drug Type: Approved Drug
# Accession No: APRD00002
CAS Registry Number: 60-56-0
