Using thionamides in hyperthyroidism

In this video from our Thyroid Disease Masterclass, endocrinologist Tracy Tylee MD will explain when to use thionamides in your patients and when NOT to use it.

Using simple illustrations and elegant animations we review the pathophysiology of thyroid dysfunction, discuss the interpretation of thyroid tests, explain how pregnancy and certain medications can alter thyroid function, and evaluate the best treatment options—this course will prepare you to confidently assess and effectively manage patients with thyroid disease.

[00:00:00] For patients with hyperthyroidism, due to overproduction of thyroid hormone, one treatment option is the use of anti-thyroid medications. There are three medications available for this with methimazole available in the United States; propylthiouracil and Carbimazole available in Europe and Asia. Normal thyroid hormone production involves the coupling of iodine to a thyroglobulin molecule, which is then converted to T4 or T3 and

[00:00:30] secreted into the bloodstream. The thionamides block the coupling of iodine and thyroglobulin and thus, block the synthesis of thyroid hormone. The thionamides are a good option for patients with Grave's disease, particularly those with active eye disease, where other treatments may be contraindicated. They are also a good option for pregnant women, where radioiodine would be contraindicated and surgery would not be a preferred treatment option. There are also good options for patients with very high thyroid hormone levels, when you want to gain control of their hyperthyroidism,

[00:01:00] prior to considering other therapies. There are some side effects from these medications. The most common being a rash, which can occur in up to 10% of patients. The other side effects are very rare but can be potentially life-threatening so you do need to be aware of those and they include agranulocytosis and hepatotoxicity. Once therapy has started, you want to measure thyroid hormone levels, initially, every 4 to 8 weeks until the patient reaches normal thyroid hormone levels. The TSH can lag behind a bit

[00:01:30] so you do not want to measure this initially but can be used for monitoring long-term therapy.