Thiamazole

Structural formula
General
Non-proprietary name	Thiamazole
other names	Methimazole; Thiamazolum; 1,3-dihydro-methyl-2 H -imidazol-2-thione;
Molecular formula	C 4 H 6 N 2 S
Brief description	white to pale brown, crystalline powder
External identifiers / databases
EC number	200-482-4
ECHA InfoCard	100,000,439
PubChem	1349907
ChemSpider	1131173
DrugBank	DB00763
Wikidata	Q419663
Drug information
ATC code	H03 BB02
Drug class	Anti-thyroid drug
properties
Molar mass	114.17 g · mol -1
Physical state	firmly
Melting point	146-148 ° C
boiling point	280 ° C (decomposition)
solubility	Easily soluble in water and dichloromethane , easily soluble to soluble in ethanol 96%
safety instructions
	Please note the exemption from the labeling requirement for drugs, medical devices, cosmetics, food and animal feed
H and P phrases	H: 317-361
	P: 280
Toxicological data	860 mg kg −1 ( LD 50 , mouse , oral ) ; 2250 mg kg −1 ( LD 50 , rat , oral ) ;
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Thiamazole is a chemical compound from the groups of imidazolines and thioureas . The compound inhibits the function of the thyroid gland and is therefore used in medicine as a medicinal substance ( anti- thyroid agent ) for the treatment of an overactive thyroid gland ( hyperthyroidism , feline hyperthyroidism ).

Working principle

Thiamazole inhibits the binding of iodine to the enzyme thyroid peroxidase and thus prevents the formation of the active thyroid hormones thyroxine and triiodothyronine .

Contraindications

In humans, the agent is contraindicated in cases of liver damage and previous hypersensitivity reactions (especially in the case of manifest thrombocytopenia ). In cats, the agent must not be used in diabetes mellitus , in humans and cats should be avoided in pregnancy or lactation .

The active ingredient could have a negative effect on the thyroid hormone level in the unborn child or in a baby fed by breast milk.

Side effects

The side effects are dose-dependent and therefore occur above all at the start of treatment, as higher doses are used here. The side effects are reversible, so they disappear again when the preparation is discontinued.

Common side effects in humans include allergic reactions (such as hives, rashes, and itching); occasionally nausea and vomiting, diarrhea or agranulocytosis occur (in 0.3 to 0.6% of cases), rarely impaired taste or drug fever . In individual cases, muscle and joint pain, jaundice, biliary congestion, lymph node disease, salivary gland swelling, inflammation of the liver, kidneys or pancreas, vascular or nerve inflammation, reduction in blood platelets and blood cells , nerve disorders, abnormal sensations, water retention in the tissue, hair loss, immune disorders Lupus erythematosus ) or severe hypersensitivity reactions ( erythema exudativum multiforme ).

In cats, side effects are seen in approximately 20% of patients. Vomiting, anorexia , lethargy , severe itching and skin lesions on the head and neck can occur. An increased tendency to bleeding and jaundice as well as changes in the blood count can occur, which is why the blood count must be checked regularly.

Chemical properties

The imidazole - derivative thiamazole is a white to faint brown crystalline powder with a characteristic odor. The boiling point is 280 ° C (decomposition). Thiamazole is soluble in water, ethanol and chloroform, but hardly soluble in ether. Galenic preparations are injection solutions and tablets.

Trade names

Monopreparations

Favistan (D), Methizol (D), Thyrozol (D), Generics (D, A)

Veterinary medicine

Felimazole , Felidale , Thiamatab , Thyronorm

literature

Hans-Joachim Frercks: Metabolism and Endocrinology. In: Jörg Braun, Roland Preuss (Ed.): Clinic Guide Intensive Care Medicine. 9th edition. Elsevier, Munich 2016, ISBN 978-3-437-23763-8 , pp. 521-538, here: pp. 534-536 ( Thyreostatika ).

Web links

Entry on thiamazole at Vetpharm, accessed on November 21, 2011.

Individual evidence

↑ ^a ^b Data sheet THIAMAZOLE CRS (PDF) at EDQM , accessed on June 27, 2009.
↑ ^a ^b ^c ^d ^e Entry on thiamazole. In: Römpp Online . Georg Thieme Verlag, accessed on November 10, 2014.
↑ ^a ^b Data sheet 2-Mercapto-1-methylimidazole from Sigma-Aldrich , accessed on April 24, 2011 ( PDF ).
↑ ^a ^b Product information Thiamazole 10mg Hexal tablets. ( Memento from September 23, 2015 in the Internet Archive ) Apotheken-Umschau, as of October 2013.
↑ Thianazole: What side effects can thiamazole have? ( Memento from November 23, 2012 in the Internet Archive ) Onmeda.de, as of October 29, 2007.

[Ph._Eur.-1] Data sheet THIAMAZOLE CRS (PDF) at EDQM , accessed on June 27, 2009.

[RÖMPP_Online-2] Entry on thiamazole. In: Römpp Online . Georg Thieme Verlag, accessed on November 10, 2014.

[Sigma-3] Data sheet 2-Mercapto-1-methylimidazole from Sigma-Aldrich , accessed on April 24, 2011 ( PDF ).

[apo-umschau-4] Product information Thiamazole 10mg Hexal tablets. ( Memento from September 23, 2015 in the Internet Archive ) Apotheken-Umschau, as of October 2013.

[5] Thianazole: What side effects can thiamazole have? ( Memento from November 23, 2012 in the Internet Archive ) Onmeda.de, as of October 29, 2007.