Thyroid Drugs

Question 1

What is the mechanism of action of propylthiouracil?

Answer 1

Blocks peroxidase, thereby inhibiting organification of iodide and coupline of thyroid hormone synthesis. It also blocks 5’deiodinase which decreases peripheral conversion of T3 to T4 (p.306)

Question 2

What is the mechanism of action of methimazole?

Answer 2

Blocks peroxidase, thereby inhibiting organification of iodide and coupline of thyroid hormone synthesis. (p.306)

Question 3

What is the clinical use for propylthiouracil?

Answer 3

Hyperthyroidism (p.306)

Question 4

What is the clinical use for methimazole?

Answer 4

Hyperthyroidism (p.306)

Question 5

What are the toxicities associated with propylthiouracil?

Answer 5

Skin rash, agranulocytosis (rare), aplastic anemia, hepatotoxicity (p.306)

Question 6

What are the toxicities associated with methimazole?

Answer 6

Skin rash, agranulocytosis (rare), aplastic anemia; teratogenic (p.306)

Question 7

What is the mechanism of action of levothyroxine?

Answer 7

Thyroxide replacement (p.306)

Question 8

What is the mechanism of action of triiodothyronine?

Answer 8

Thyroxide replacement (p.306)

Question 9

Which drugs are thyroxine replacements?

Answer 9

Levothyroxine, triiodothyronine (p.306)

Question 10

What are the clinical uses for levothyroxine?

Answer 10

Hypothyroidism, myxedema (p.306)

Question 11

What are the clinical uses for triiodothyronine?

Answer 11

Hypothyroidism, myxedema (p.306)

Question 12

What are the toxicities associated with levothyroxine?

Answer 12

Tachycardia, heat intolerance, tremors, arrythmias (p.306)

Question 13

What toxicities are associated with triiodothyronine?

Answer 13

Tachycardia, heat intolerance, tremors, arrythmias (p.306)