Antithyroid drugs Flashcards
What is the most commonly used anti-thyroid drug?
Carbimazole - propylthiouracil should be reserved for patients who are intolerant of carbimazole or for those who experience sensitivity reactions to carbimazole.
Over-treatment with antithyroid drugs can result in the rapid development of hypothyroidism and should be avoided particularly during pregnancy because it can cause what?
Fetal goitre.
What is ‘bocking-replacement’ therapy?
How long is it given for usually?
Combination of carbimazole with levothyroxine sodium daily, may be used in a blocking-replacement regimen for usually 18 months. NOT SUITABLE DURING PREGNANCY.
When is blocking-replacement therapy not suitable?
During pregnancy.
When would iodine be prescribed to a patient with hyperactive thyroid?
10-14 days before partial thyroidectomy: however, there is little evidence of a beneficial effect.
When would radioactive sodium iodide (131)I used?
Increasingly for the treatment of thyrotoxicosis at all ages.
What beta blocker can be used for rapid relief of thyrotoxic symptoms?
Propranolol (hydrochloride)
[Nadolol is also used]
What impact do beta blockers have on TFT results?
None.
How is thyroid storm treated? [5]
Emergency treatment consisting of: IV fluids, Propranolol hydrochloride Hydrocortisone (as sodium succinate) Oral iodine solution Carbimazole or propylthiouracil (via NG tube if needed)
What is the anti-thyroid drug of choice during the first trimester, why?
Propylthiouracil because carbimazole has been associated (rarely) with congenital defects, including aplasia cutis of the neonate.
What is the anti-thyroid drug of choice in the second trimester, why?
Consider switching from propylthiouracil to carbimazole due to the risk of hepatotoxicity.
Both antithryoid drugs can cross the placenta in high doses so the lowest effective dose should be used.
