Propylthiouracil and methimazole

Question 1

MOA

Answer 1

block peroxidase, inhibiting organification of iodide and coupling of thyroid hormone synthesis.

Propylthiouracil also blocks 5’ deiodinase, which decreases peripheral conversion of T4 to T3

Question 2

Clinical use

Answer 2

Hyperthyroidism

Question 3

Toxicity

Answer 3

skin rash,
AGRANULOCYTOSIS (rare)
Anaplastic anemia
hepatotoxicity (prophylthiouracil)
teratogen (methimazole)