Some compounds having thionamide structure inhibit thyroid functions. Such antithyroid thionamides include mercaptomethylimidazole (methimazole), thiourea and propylthiouracil, of which mercaptomethylimidazole is widely used to treat hyperthyroidism. Undesirable side effects develop from these drugs due to extrathyroidal actions. Antithyroid thionamides inhibit lactoperoxidase which contributes to the antibacterial activities of a number of mammalian exocrine gland secretions that protect a variety of mucosal surfaces. These drugs stimulate both gastric acid and pepsinogen secretions, thereby augmenting the severity of gastric ulcers and preventing wound healing. Increased gastric acid secretion is partially due to the H2 receptor activation, and also through the stimulation of the parietal cell by intracellular generation of H2O2 following inactivation of the gastric peroxidase-catalase system. Severe abnormalities may develop in blood cells and the immune system after thionamide therapy. It causes agranulocytosis, aplastic anemia, and purpura along with immune suppression. Olfactory and auditory systems are also affected by these drugs. Thionamide affects the sense of smell and taste and also causes loss of hearing. It binds to the Bowman's glands in the olfactory mucosa and causes extensive lesion in the olfactory mucosa. Thionamides also affect gene expression and modulate the functions of some cell types. A brief account of the chemistry and metabolism of antithyroid thionamides, along with their biological actions are presented.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/s0378-4274(01)00539-2 | DOI Listing |
J Clin Med
November 2024
Section of Endocrinology and Investigative Medicine, Imperial College London, London W12 ONN, UK.
Liver dysfunction can occur in patients presenting with thyrotoxicosis, due to several different aetiologies. A 42-year-old man had mild liver dysfunction on presentation with hyperthyroidism due to Graves' disease (GD): ALT 65 (0-45 IU/L), fT4 41.2 (9-23 pmol/L), fT3 > 30.
View Article and Find Full Text PDFEndocr Regul
January 2024
Department of General Medicine, Baroda Medical College and SSG Hospital, Vadodara, India.
Sisli Etfal Hastan Tip Bul
September 2024
Department of General Surgery, University of Health Sciences Türkiye, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Türkiye.
Hyperthyroidism is a clinical condition that develops due to the excessive production and secretion of thyroid hormones by the thyroid gland, leading to an elevated concentration of thyroid hormones in tissues. Hyperthyroidism is characterized by low TSH and elevated T3 and/or T4, with the most common causes being Graves' disease, toxic multinodular goiter, and solitary toxic adenoma. T3 is the peripherally active form of thyroid hormone, affecting nearly each tissue and system.
View Article and Find Full Text PDFEndocrinol Metab (Seoul)
December 2024
Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Graves' hyperthyroidism is characterized by stimulation of the thyroid gland by thyroid-stimulating hormone receptor antibodies (TRAbs). Antithyroid drug (ATD) continuation is recommended as long as the thyroid gland is stimulated. Goiter size, thyroidal 123I uptake, serum thyroglobulin level, and TRAb positivity are reliable markers of thyroid stimulation.
View Article and Find Full Text PDFEur Thyroid J
December 2024
Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka, Japan.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!