ATC Group: H03BB Sulfur-containing imidazole derivatives

The World Health Organization's ATC classification organizes medical drugs based on therapeutic properties, chemical composition, and anatomy. It helps make essential medicines readily available globally and is widely used in the pharmaceutical industry.

Position of H03BB in the ATC hierarchy

Level Code Title
1 H Systemic hormonal preparations, excl. Sex hormones and insulins
2 H03 Thyroid therapy
3 H03B Antithyroid preparations
4 H03BB Sulfur-containing imidazole derivatives

Group H03BB contents

Code Title
H03BB01 Carbimazole
H03BB02 Thiamazole
H03BB52 Thiamazole, combinations

Active ingredients in H03BB

Active Ingredient

Carbimazole, a thionamide, is a pro-drug which undergoes rapid and virtually complete metabolism to the active metabolite, thiamazole, also known as methimazole. The method of action is believed to be inhibition of the organification of iodide and the coupling of iodothyronine residues which in turn suppress the synthesis of thyroid hormones.

Thiamazole inhibits dose-dependently the incorporation of iodine into tyrosine and thereby the neosynthesis of thyroid hormones. This property permits symptomatic therapy of hyperthyroidism regardless of its cause.

Related product monographs

Document Type Information Source  
 NEOMERCAZOLE Tablet MPI, EU: SmPC Health Products Regulatory Authority (IE)
 TAPAZOLE Tablet MPI, US: SPL/Old FDA, National Drug Code (US)