Thiamazole

C11H9I3N2O4 117-96-4) see Metrizoic acid aminoacetaldehyde diethyl acetal (C H 5N02 645-36-3) see Thiamazole p-aminoacetanilide... 

CjH NS 556-61-6) see Betanidine Thiamazole 5-methylisothiosemicarbazide hydriodide (CjHnINjS 35600-34-1) see Guanoxabenz 5-methylisothiourea... 

A solution containing 10-60 ug thiamazole was buffered at pH 5.6, treated with NaN3 and then with 0.02 M iodine solution, left 10 minutes and titrated for unchanged iodine with 0.02 M Na3As03. The method was useful in determining methimazole in compound drugs provided they... 

In this method the reaction of diphenylpicrylhydra-sine with methimazole (thiamazole) was sufficiently rapid for its use in a spectrophotometric assay. 

Methimazole also directly disrupts thyroxine and triiodothyronin sysnthesis in the thyroid gland, and it is used for the same indications as propylthiouracil and methylthiouracil to treat hyperfunctioning thyroid glands in patients with Basedow s disease. Synonyms of this drug are merazolil, thiamazole, metothyrin, timidazol, and others. 

The available agents with antithyroid activity are the thioamides propylthiouracil, carbimazole and methimazole also known as thiamazole. Their thio-carbamide group is indispensable for antithyroid activity. The mechanism of action is complex. The most important action is the prevention of hormone synthesis by an inhibition of the thyroid peroxidase-catalyzed reactions involved in iodine organification. These agents also block the coupling of the iodoty-rosines. 

Neuritis has been described in patients taking thiamazole (8,9). 

Retrobulbar neuritis has been reported in a patient taking thiamazole (12). 

The risk of agranulocytosis has been estimated during several surveys. A large European-Israeli study (23) showed a risk of about 3 per 10 000 users. However, the mortality in this survey was small (one in 45 cases) (SEDA-13, 376). In two hospital surveys of agranulocytosis (24,25) there was an increased risk in women aged over 40 years and when the dose of thiamazole (thiamazole) was more than 40 mg/day. In vitro lymphocyte testing can confirm the sensitization of the immune... 

Aplastic anemia developed in a 58-year-old woman taking thiamazole for the third time she responded well to drug withdrawal and treatment with human granulocyte colony stimulating factor (42). 

Of 14 cases of suspected drug-induced liver disease presenting to a gastroenterology department over a 3-year period, one was thought to be related to thiamazole, with a hepatitic pattern of liver function tests in a 39-year-old woman 6 days after the start of therapy recovery was swift and complete (48). Delayed cholestatic hepatitis without antineutrophil cytoplasmic antibodies has been reported (49), and there have been fatal cases of hepatic necrosis (SEDA-21, 438) (7). 

Acute pancreatitis and parotitis without antineutrophil cytoplasmic antibodies has been attributed to thiamazole (53). 

Allergic reactions manifesting as fever, urticaria or other rashes, and arthralgia occur in 1-5% of patients taking antithyroid drugs. There has been a report of thiamazole-induced hypersensitivity syndrome associated with reactivation of human herpes virus 6 and cytomegalovirus (57). 

Several cases of collagen-like or lupus-like disease have been reported (joint pain, skin rash, and positive antinuclear antibodies) during treatment with either propylthiouracil or thiamazole (SEDA-8, 372) (SEDA-10, 368). Some cases of general vasculitis can be fatal, although high-dose glucocorticoid therapy can be helpful (90). 

Aplasia cutis congenita has been attributed to carbima-zole, or its active metabolite thiamazole, given during... 

Additional cases of aplasia cutis congenita in thiona-mide-exposed infants associated with other congenital abnormalities, such as choanal atresia, esophageal atresia, imperforate anus, and cardiovascular defects, were also reviewed. This pattern of abnormalities has previously led to the term methimazole [thiamazole] embryopathy (95). 

A 3-year-old child, whose mother had been treated for Graves hyperthyroidism with thiamazole throughout pregnancy, had two scalp lesions and other abnormalities of tissues of ectodermal origin, including dystrophic nails and syndactyly. 

Wada N, Mukai M, Kohno M, Notoya A, Ito T, Yoshioka N. Prevalence of serum anti-myeloperoxidase antineutrophil cytoplasmic antibodies (MPO-ANCA) in patients with Graves disease treated with propylthiouracil and thiamazole. Endocr J 2002 49(3) 329-34. 

Common Name Mercazolyl(um) Methimazole Methymazole Thiamazole Tiamazol... 

The reaction of the l-(2,2-diethoxyethyl)-3-methylthiourea with sulfuric acid yield thiamazole. 

Diethoxyethyl)methylamine reacted with potassium thiocyanate in the presence of hydrochloric acid and give the thiamazole, yellow crystallic precipitate, melting point 144°-147°C. 

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