Thyroid/Anti-thyroid drugs Flashcards
What is levothyroxine?
T4
How do high levels of T4 affect bone?
High T4 leads to bone loss in premenopausal women
What is liothyronine?
T3
When is liothyronine required?
In hypothyroidism when rapid onset of action is required
(myxedema coma)
Can also be used in a patient undergoing radioiodine therapy
Which beta blocker can also inhibit peripheral conversion of T4 to T3?
Propranolol
Does PTU or MMI inhibit peripheral conversion of T4 to T3?
PTU partially inhibits deiodination
Do PTU and MMI inhibit release of preformed T4?
No
What are common adverse effects associated with PTU and MMI?
Skin rash, joint pain Hepatotoxicity (PTU >>MMI) ANCA-positive vasculitis (PTU>MMI) Agranulocytosis (PTU=MMI) Teratogenicity MMI >>PTU
When would you use PTU vs MMI?
PTU in 1st trimester pregnancies
MMI in all other cases
What is the MOA of iodine administration?
Acutely and rapidly inhibits thyroid hormone secretion
Inhibits thyroid synthesis (Wolff-CHaikoff effect, transient)
Decreases thyroid organ vascularity
When would you administer high doses of iodine?
Severe hyperthyroidism (thyroid storm)
Preoperatively in patients undergoing thyroidectomy
Adjunct therapy following any radioactive/antithyroid drug
After major nuclear accidents to prevent radioiodine uptake…
When do you use radioactive iodine therapy?
Hyperthyroidism
Toxic nodular goiter
When do you use cholestyramine?
THyroid storm-
How does cholestyramine help in a thyroid storm?
Prevents absorption of thyroid hormone
