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Revision as of 17:36, 9 November 2011 by Beetstra (talk | contribs) (Script assisted update of identifiers for the Chem/Drugbox validation project (updated: 'DrugBank').)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff) Not to be confused with metamizole. Pharmaceutical compound | |
| Clinical data | |
|---|---|
| AHFS/Drugs.com | Monograph |
| MedlinePlus | a682464 |
| Pregnancy category |
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| Routes of administration | Oral |
| ATC code | |
| Legal status | |
| Legal status |
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| Pharmacokinetic data | |
| Bioavailability | 93% |
| Protein binding | None |
| Metabolism | Hepatic |
| Elimination half-life | 5-6 hours |
| Excretion | Renal |
| Identifiers | |
IUPAC name
| |
| CAS Number | |
| PubChem CID | |
| DrugBank | |
| ChemSpider | |
| UNII | |
| KEGG | |
| ChEBI | |
| ChEMBL | |
| CompTox Dashboard (EPA) | |
| ECHA InfoCard | 100.000.439  |
| Chemical and physical data | |
| Formula | C4H6N2S |
| Molar mass | 114.17 g/mol g·mol |
| 3D model (JSmol) | |
| Melting point | 146 °C (295 °F) |
| Solubility in water | 2.75 mg/mL (20 °C) |
SMILES
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InChI
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| (what is this?) (verify) | |
Methimazole (also known as Tapazole or Thiamazole or MMI) is an antithyroid drug, and part of the thioamide group.
Indications
Methimazole is a drug used to treat hyperthyroidism, a condition that usually occurs when the thyroid gland is producing too much thyroid hormone. It may also be taken before thyroid surgery to lower thyroid hormone levels and minimize the effects of thyroid manipulation.
Mechanism of action
Methimazole inhibits the addition of iodine to thyroglobulin by the enzyme thyroperoxidase, a necessary step in the synthesis of triiodothyronine (T3) and thyroxine (T4).
It does not inhibit the action of the sodium-dependent iodide transporter located on follicular cells' basolateral membranes. Inhibition of this step requires competitive inhibitors such as perchlorate and thiocyanate.
It acts at CXCL10.
Adverse effects
 | This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (November 2011) (Learn how and when to remove this message) |
It is important to monitor any symptoms of fever or sore throat while taking methimazole; this could indicate the development of agranulocytosis, an uncommon but severe side effect resulting from a drop in the white blood cell count (to be specific, neutropenia, a deficiency of neutrophils). A complete blood count (CBC) with differential is performed to confirm the suspicion, in which case the drug is discontinued. Administration of recombinant human granulocyte colony-stimulating factor (rhG-CSF) may increase recovery.
Other side effects include
- skin rash
- itching
- abnormal hair loss
- upset stomach
- vomiting
- loss of taste
- abnormal sensations (tingling, prickling, burning, tightness, and pulling)
- swelling
- joint and muscle pain
- drowsiness
- dizziness
- decreased white blood cells
- decreased platelet
- Aplasia cutis congenita (prenatal exposure)
Drug interactions
Adverse effects may occur for individuals who:
- Take anticoagulants ('blood thinners') such as warfarin (Coumadin), diabetes medications, digoxin (Lanoxin), theophylline (Theobid, Theo-Dur), and vitamins
- Have ever had any blood disease, such as decreased white blood cells (leukopenia), decreased platelets (thrombocytopenia), or aplastic anemia, or liver disease (hepatitis, jaundice)
- Are pregnant, or going to become pregnant, or are breast-feeding. An alternative anti-thyroid drug, propylthiouracil, is often substituted during pregnancy or breast-feeding. If pregnancy occurs while taking methimazole, switching to propylthiouracil may be an alternative. Early studies suggested that methimazole may harm the fetus; however, more recent studies suggest this may not be the case.
- Are going to have surgery, including dental surgery.
See also
References
- Nakamura H, Noh JY, Itoh K, Fukata S, Miyauchi A, Hamada N (2007). "Comparison of methimazole and propylthiouracil in patients with hyperthyroidism caused by Graves' disease". The Journal of clinical endocrinology and metabolism. 92 (6): 2157–62. doi:10.1210/jc.2006-2135. PMID 17389704.
{{cite journal}}: Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) - Crescioli C, Cosmi L, Borgogni E; et al. (2007). "Methimazole inhibits CXC chemokine ligand 10 secretion in human thyrocytes". J. Endocrinol. 195 (1): 145–55. doi:10.1677/JOE-07-0240. PMID 17911406.
{{cite journal}}: Explicit use of et al. in:|author=(help); Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link)
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