Pharmacotherapy of Thyroid Disease

Question 1

levothyroxine

Answer 1

T4

Question 2

liothyronine

Answer 2

T3

Question 3

methimazole

Answer 3

antithyroid agent

Question 4

propylthiouracil

Answer 4

PTU

antithyroid agent

Question 5

potassium iodide

Answer 5

antithyroid agent

Question 6

NIS

Answer 6

sodium iodine symporter
-transport of iodine into thyroid gland

inhibited by SCN-, TcO4-, ClO4-

Question 7

pendrin

Answer 7

transport of iodide to follicular lumen

Question 8

thyroidal peroxidase

Answer 8

oxidizes iodide to iodine

then to MIT and DIT (organification)

Question 9

thyroglobulin

Answer 9

combines with iodine to form thyroid hormones

two DIT in TH - T4
DIT and MIT in TH - T3

Question 10

thyroid hormone release

Answer 10

exocytosis and proteolysis of thyroglobulin at apical colloid border

high levels of iodide blocks the proteolysis

Question 11

ratio of T4 to T3

Answer 11

5:1

Question 12

thyroid hormone transport

Answer 12

plasma protein bound
-to thyroxine binding globulin (TBG)

0.04% in free form

Question 13

3-5-3 triiodothyronine

Answer 13

T3

3-4x more potent

Question 14

3-3-5 triiodothyronine

Answer 14

rT3

inactive

Question 15

amiodarone

Answer 15

inhibits 5’ deiodinase for T4 to T3

low T3 and high rT3

Question 16

block conversion of T4 to T3

Answer 16

amiodarone
iodinate contrast media
beta blockers
corticosteroids
illness
starvation

Question 17

TSH signaling

Answer 17

adenylyl cyclase

Question 18

T4 and T3 feedback

Answer 18

negative on hypothalamus and pituitary

Question 19

acute psychosis or cold

Answer 19

activate thyroid axis

Question 20

somatostatin and dopamine

Answer 20

inhibit TSH release

Question 21

large amounts of iodine

Answer 21

inhibit TSH release

Question 22

thyroid hormone MOA

Answer 22

T4 to cytoplasm - 5 deiodinase converts to T3

T3 to nucleus

thyroid receptor bound to DNA at TRE

T3 binds TR - displaces corepressor and allows binding of coactivator

binds RXR on TRE - activates gene transcription

Question 23

thyroid effects

Answer 23

activation of nuclear receptors lead to protein synthesis

lag time of effects - hours or days

Question 24

warm, sweaty, tachycardia, increased appetite, nervous

Answer 24

hyperthyroid

Question 25

cool, pale, bradycardia, decreased appetite, lethargic

Answer 25

hypothyroid

Question 26

hyperthyroid T3 and T4

Answer 26

clearance increased | half life decreased

Question 27

hypothyroid T3 and T4

Answer 27

clearance decreased | half life increased

Question 28

agents increase CYP and enhance thyroid hormone degradation

Answer 28

``` rifampin phenobarbital carbamazepine phenytoin HIV protease inhibitor ```

Question 29

agents interfere T4 absorption

Answer 29

``` oral bisphosphanate bile acid sequestrant cipro PPIs sucralafate antacids bran soy coffee ```

Question 30

agents induce autoimmune thyroid disease

Answer 30

IFN-alpha IFN-beta lithium amiodarone

Question 31

agents inhibit conversion T4 to T3

Answer 31

``` radiocontrast amiodarone beta-blocker corticosteroid PTU ```

Question 32

levothyroxine

Answer 32

T4 | -preferred - cheaper, easy lab monitoring, long half life

Question 33

liothyronine

Answer 33

T3 - 3-4x more potent - shorter half life risk of cardiotoxicity

Question 34

cardiac disease

Answer 34

no T3

Question 35

thioamides

Answer 35

methimazole | PTU

Question 36

methimazole MOA

Answer 36

inhibit thyroid peroxidase -block organification block coupling MIT and DIT

Question 37

propylthiouracil MOA

Answer 37

inhibit thyroid peroxidase -block organification block coupling MIT and DIT

Question 38

methimazole vs. PTU

Answer 38

methimazole is DOC -10x more potent both cross placenta - to fetal thyroid - risk hypothyroidism

Question 39

pregnancy antithyroid drug

Answer 39

PTU - first trimester more protein bound - so crosses placenta less readily

Question 40

thyroid storm

Answer 40

PTU

Question 41

severe hepatitis

Answer 41

PTU black box warning

Question 42

agranulocytosis

Answer 42

in PTU and methimazole

Question 43

anion inhibitors

Answer 43

perchlorate pertechnetate thiocyanate competitively inhibit iodide transport

Question 44

potassium iodide MOA

Answer 44

inhibit iodide organification and hormone release inhibit hormone release and decrease size and vascularity of hyperplastic gland

Question 45

reduction in size of hyperplastic gland

Answer 45

potassium iodide

Question 46

acneiform rash and swollen salivary glands

Answer 46

seen with potassium iodide - adverse effect

Question 47

radioactive iodide MOA

Answer 47

emission of beta rays -destruction of thyroid gland concentrates in thyroid and stored in follicles

Question 48

DOC for hashimotos

Answer 48

levothyroxine - T4 drug levels reached in 6-8 weeks

Question 49

restlessness, insomnia and accelerated bone grwoth

Answer 49

thyroxine in children

Question 50

nervous, heat intolerance, palps, tachy, weight loss

Answer 50

thyroxine in adults

Question 51

myxedema coma

Answer 51

end stage of untreated hypothyroid -medical emergency intubation, ventilation - drugs IV**

Question 52

a fib and osteoporosis

Answer 52

overtreatment with T4

Question 53

hypothyroid women

Answer 53

often infertile

Question 54

pregnancy

Answer 54

important to replace thyroid hormones in hypothyroid mother | -important for fetal brain

Question 55

young patient, small gland, mild graves tx

Answer 55

medical - methimazole (or PTU)

Question 56

old patient, large gland, MNG graves tx

Answer 56

surgical - thyroidectomy treat with antithyroid until euthyroid** potassium iodide - to diminish vascularity

Question 57

radioiodine tx o fgraves

Answer 57

without heart disease over 21yo

Question 58

adjuncts to antithyroid meds

Answer 58

beta blockers diltiazem (CCB)

Question 59

tx of thyroid storm

Answer 59

``` beta blockers potassium iodide PTU hydrocortisone supportive therapy ```