Endocrine 4 (Thyroid)

Question 1

Thyroxine

Answer 1

T4

Question 2

Tri-Iodothyronine

Answer 2

T3

Question 3

Levothyroxine

Answer 3

Thyroid Replacement
T4 (Most Common)

Question 4

Liothyronine

Answer 4

Thyroid Replacement
T3 (Most Active)
- Only for emergencies like Myxedema

Question 5

Radioiodine

Answer 5

Treats Hyperthyroidism
1st Line Treatment using (131)I

Beta Particles of Isotope have a:
- Short range (Weakly penetrating), and only stay within the thyroid
- Cytotoxic action, destroys the thyroid gland

Question 6

Propylthiouracil

Answer 6

Antithyroids (Thioamides)
- More rapid pharmacological action
- Inhibits thyroperoxidase
- Inhibits iodinated couping
- Inhibit deiodination from T4 to T3

Question 7

Methimazole

Answer 7

Antithyroids (Thioamides)
- Inhibits thyroperoxidase
- Inhibits iodinated couping
- Inhibit deiodination from T4 to T3

Question 8

Carbimazole

Answer 8

Antithyroids (Thioamides)
Prodrug
Is converted into Methimazole

Question 9

Lugol Iodine

Answer 9

Antithyroid
- Causes an excess of iodide

Negative Feedback
Reduce Vascularity
Reduce H2O2

Question 10

Propranolol

Answer 10

Controls adverse effects of hyperthyroid

1. Inhibits beta 2
2. Decrease AC and cAMP and PKA
3. Also prevents peripheral conversion of T4 to T3