Thyroid Drugs

Question 1

Hyperthyroidism Drugs

Answer 1

Thioamides - PTU, Methimazole
Iodine (Radioactive Iodine)
Iodides (Potassium Iodide, Lugol’s)
Beta Blockers ( Propanolol, Esmolol, Metoprolol, Atenolol)

Question 2

Hypothyroidism Drugs

Answer 2

Levothyroxine - T4
Liothyronine - T3
Liotrix

Question 3

Mains steps in thyroid hormone synthesis

Answer 3

Iodide Trapping (mediated by pendrin)
Iodide Oxidation (by TPO)
Iodine Organification (by TPO)
Coupling (by TPO)
Proteolysis

Question 4

MOA: PTU

Answer 4

inhibits TPO

inhibits organification

inhibits peripheral conversion of T4 to T3

Question 5

MOA: Methimazole

Answer 5

Inhibits TPO

inhibits organification

Question 6

AE of Thioamides

Answer 6

Agranulocytosis

granulocytes<500cells/mm3

Question 7

MOA: Radioactive Iodine

Answer 7

Permanent destruction of thyroid parenchyma

Question 8

SE: RADIOACTIVE IODINE

Answer 8

permanent hypothyroidism

risk for developing papillary thyroid CA

Question 9

MOA: Potassium Iodides

Answer 9

inhibits organification and hormone release

reduces size and vascularity of thyroid gland

Question 10

MOA: Beta Blockers

Answer 10

Adjunct drug

for control of HR and other cardiac abnormalities in severe thyrotoxicosis

Propanolol - can inhibit peripheral conversion of T4 to T3

Question 11

Drug of choice for hyperthyroid pregnant

Answer 11

PTU given first trimester

Question 12

DOC for hyperthyroid nonpregnant

Answer 12

methimazole

Question 13

Other name for methimazole

Answer 13

Thiamazole

Question 14

Hyperthyroid drugs that can cause Aplasia Cutis congenita

Answer 14

Methimazole and Carbimazole

Question 15

Preferred treatment by most patients because it offers permanent cure of thyrotoxicosis without surgery

Answer 15

Radioactive Iodine

Question 16

Contraindicated in pregnant women or nursing mothers

Answer 16

Radioactive iodine

Question 17

Thyroid Storm treatment

Answer 17

PTU - block synthesis
Iodides - blocks release
Propanolol
Hydrocortisone

Question 18

Drugs that inhibit peripheral conversion of T4 to T3

Answer 18

PTU
Propanolol
Hydrocortisone

Question 19

What drugs can cause drug-induced hyperthyroidism?

Answer 19

Clofibrate
Amiodarone
Methadone

Question 20

Amiodarone- induced Thyroid Disease

Answer 20

Can cause both

hyperthyroidism
tx: thioamides, corticosteroids

hypothyroidism
tx: levothyroxine

Question 21

Utmost concern in treating hyperthyroidism in pregnant patients

Answer 21

Choanal and esophageal atresia in MMI treated

Maternal hepatotoxicity in PTU-treated

Question 22

Mainstay of treatment of postpartum hyperthyroidism

Answer 22

MMI

Question 23

What will you do if your patient developed agranulocytosis during treatment with thioamides?

Answer 23

discontinue thioamides
give recombinant G-CSF (Filgrastin)
treat with prophylactic broad spectrum abx

Question 24

Anion Inhibitors

Answer 24

perchlorate (ClO4-)
pertechnetate (TcO4-)
thiocyanate (SCN-)

Question 25

MOA: anion inhibitors

Answer 25

blocks uptake of iodide by the gland

Question 26

MOA: Levothyroxine

Answer 26

activation of nuclear receptors resulting in gene expression with RNA formation and protein synthesis

Question 27

Uses: Levothyroxine

Answer 27

Hypothyroidism, myxedema coma

Question 28

Onset of action of radioactive iodine

Answer 28

6-12 weeks

Question 29

Maximal effect of radioactive iodine seen in

Answer 29

3-6 months

Question 30

onset of action within hours

Answer 30

PTU

Propanolol

Question 31

Maximum effect of levothryroxine seen in

Answer 31

6-8 weeks