NeoMercazole is an anti-thyroid substance which depresses the formation of thyroid hormone. It reduces the uptake and concentration of inorganic iodine by the thyroid but its main effect is to reduce the formation of di-iodotyrosine and thyroxine. Carbimazole is absorbed rapidly from the gastro-intestinal tract and is widely distributed throughout the body.
Contra-Indications
Hypersensitivity to carbimazole or other thiourea antithyroid agents. Carbimazole should be given with the utmost caution, or not at all, if there is any degree of tracheal obstruction, as high dosages may produce thyroid enlargement and obstructive symptoms may become marked.
Direction for Use
10 mg to 60 mg daily according to the severity of the disorder. The dose should be gradually reduced to the smallest amount which will control the disease. Daily dosage should be divided.
Caution
Carbimazole may be given during pregnancy to a thyrotoxic patient, but the smallest effective dose should be used lest overdosage adversely affects the foetus. Carbimazole crosses the placenta and is excreted into the breast milk. Carbimazole may, therefore, cause foetal or neonatal hypothyroidism and goitre. Adverse effects occur most frequently during the first 8 weeks of treatment.
