Thyroid and Antithyroid

Question 1

T4 Half life

Answer 1

5-7 days

Question 2

T3 half life

Answer 2

1 day

Question 3

Case: Px presents with weight loss, tremors, hyperdefecation and exopthalmos. Dx?

Answer 3

Grave’s Dse (Hyperthyroidism)

Question 4

Case: Px presents with weight loss, tremors, hyperdefecation and exopthalmos. tx?

Answer 4

Propylthiouracil
Levothyroxine
Methimazole

Question 5

Inhibits conversion of T4 to T3

Answer 5

Propylthiouracil

Question 6

Inhibits iodide concentration (Trapping)

Answer 6

Pertechnetate

Perchlorate

Question 7

Inhibits Iodination/ Organification

Answer 7

Thioamides, Iodide

Question 8

Inhibits Coupling

Answer 8

Thioamides, Methimazole

Question 9

Inhibits Hormone release

Answer 9

Li salts, Iodides

Question 10

Inhibits deiodination

Answer 10

PTU

Question 11

Inhibits peripheral action (conversion of T4 -> T3)

Answer 11

Beta blocker
Corticosteroids
Ipodate
PTU
Amiodarone

Question 12

PTU
Methimazole
Carbimazole

Answer 12

Thioamides

Question 13

Thioamides MOA

Answer 13

Irreversible binding of THYROID PEROXIDASE thus inhibiting it

Question 14

PTU:Methimazole dosage

Answer 14

3 times a day (shorter duration): once a day

Question 15

Which crosses the placenta?

a. Methimazole
b. PTU
c. Both

Answer 15

C

PTU crosses less readily

Question 16

Thioamides ADR

Answer 16

Most common: RASH

Rare and dangerous: AGRANULOCYTOSIS

Question 17

DOC for thyrotoxicosis

Answer 17

Methimazole

*PTU is hepatotoxic

Question 18

Most common consequence of maternal hypothyroidism treated with Methimazole

Answer 18

Choanal Atresia- nasal septum malformation

Pwede ring aplasia cutis

Question 19

Recommended for pregnant patients

Answer 19

PTU in the first trimester, Methimazole after

Why switch? PTU is Hepatotoxic!

Question 20

Useful in preparation in surgery, THYROID STORM

Answer 20

Iodide

Question 21

2 Phenomenons which Iodide can induce

Answer 21

Jod-Basedow (Hyper), Wolff-Chaikoff (Hypo)

Question 22

Acute onset of Iodide effects

Answer 22

2-7 days

Question 23

When is Lugol’s solution and Potassium iodide given?

Answer 23

AFTER admin of antithyroids

*Not before, can induce hyperthyroidism

Question 24

Fetal goiter in chronic iodide use

Answer 24

Iodide can readily cross the placenta and can be excreted in the breastmilk

*Normal excretion- urine

Question 25

Iodide ADR

Answer 25

Metallic taste rash Fetal goiter

Question 26

1st isotope used for treatment of thyrotoxicosis

Answer 26

Radioactive Iodine (Oral)

Question 27

Maximum effects of RI can be felt within

Answer 27

3-6 months

Question 28

Advantages of RI

Answer 28

Easy admin Less costly Absence of pain

Question 29

Consequence of maternal use of RI during admin or 6-12 mos after

Answer 29

Destruction of Fetal thyroid gland

Question 30

RI ADR

Answer 30

Sialitis (mag dictionary ka tang ina mo)

Question 31

RI admin of 100-200mg

Answer 31

Thyroid Cancer

Question 32

RI admin of 500 mg

Answer 32

Leukemia

Question 33

they don't really lower thyroid levels

Answer 33

Beta Blockers

Question 34

Beta Blockers

Answer 34

antagonize the target organ effects of thyroid hormone

Question 35

Beta Blockers effect on Hyperthyroid patients

Answer 35

Lowering heart rate especially for those who have palpitations Reducing tremors

Question 36

Propanolol is the same with PTU in?

Answer 36

Inhibiting conversion of T4-T3

Question 37

Main Indication of Propanolol

Answer 37

Thyroid Storm

Question 38

Difference of propanolol to other B Blockers

Answer 38

Shorter duration (4-6 hrs), must be given 3 times a day (oral)

Question 39

Case: 55 y/o female with cold intolerance, weight gain, easy fatigability, edema and diffuse goiter. Dx?

Answer 39

Hypothyroidism

Question 40

Case: 55 y/o female with cold intolerance, weight gain, easy fatigability, edema and diffuse goiter. Tx?

Answer 40

Levothyroxine

Question 41

Levothyroxine>Liothyronine

Answer 41

Levo (L-T4) is IV, Fair to Good absorption, longer duration (Half life- 7days) and more likely to bind to protein Liothyronine is not commercially available

Question 42

Levothyroxine MOA

Answer 42

Suppression of TSH

Question 43

Drug that can increase serum levels of T4

Answer 43

Estrogen- increases TBG *Acute infectious hepatitis

Question 44

Drugs that decrease TBG

Answer 44

Androgens, Glucocorticoids *Nephrotic Syndrome

Question 45

Drugs affecting Thyroid Hormone Binding

Answer 45

Phenytoin Diazepam Salicylates

Question 46

Drugs that interfere absorption of L-T4

Answer 46

Cholestyramine Al Hydroxide Fe Sulfate Ca

Question 47

Thyroid hormone dose requirements _____ during pregnancy a. Inc b. Dec c. Stay the same

Answer 47

A