Thyroid and Antithryoid

Question 1

drugs that are thyroid preps

Answer 1

Levothyroxine (T4)

Liothyronine (T3)

Liotrix (T3, T4)

Question 2

Adjunct therapy agents

Answer 2

propranolol

diltiazem

barbituates

bile acide sequetrants

Question 3

Thyroid hormone synthesis:

iodide uptake into thyroid gland by the 1

2 mediated oxidation of iodide to iodine

Answer 3

1. sodium/iodide symporter

2. peroxidase

Question 4

when is transcription repressed

Answer 4

absence of thyroid hormone; unbound T3 receptor

Question 5

what converts T4 to T3

Answer 5

5’-deiodinase

Question 6

when is thyroid synthesis inhibited and when is it promotes

Answer 6

High = inhibit NIS, iodination, hormone release

Low = stimulate TSH release and T3 production

Question 7

what is the goal in treating hypothyroidism

Answer 7

increase [T4] in blood

normalize TSH

alleviate sx

Question 8

what is the tx of choice for hypothyroidism

Answer 8

Levothyroxine

• activation of T3 receptors
• 7 day T1/2

Question 9

why treating hypothyroidism what is a special consdieration that needs to be addressed?

Answer 9

Coronary artery disease

• in elderly there is often underlying CAD. Thyroid hormone is protective. Tx. must be done carefully not to provoke arrhythmias, angina, or MI

Question 10

In graves disease autoantibodies stimulate TSH receptors and increase production of T3 and T4; would you expect TSH levels to be high or low

Answer 10

low

Question 11

how would you treat hyperthryoidism

Answer 11

methimazole

propylthiouracil

(thioamides)

Question 12

MOA of thioamides

Answer 12

inhibit peroxidase rxn, iodine organification, and coupling of iodotyrosines

Question 13

what is a consideration for the use of thioamides

Answer 13

low levels cross placental barrier - risk of fetal hypothyroidism

Question 14

which thioamide would be preferred if femaile is in 1st trimester of pregnancy? why?

Answer 14

Propylthiouracil - more bound to plasma proteins

Question 15

which thioamide is used for thyroid storm due to rapid absorption

Answer 15

propylthiouracil

Question 16

which thioamide has a black box warning for severe hepatitis

Answer 16

propylthiouracil

Question 17

what does the antithyroid agents potatssium iodide and lugol’s solution due to iodide stores?

Answer 17

increases intraglandular iodide stores thus delaying onset of thioamide therapy

Question 18

why are iodides often used in combo with other agents

Answer 18

normally only inhibit for 2-8 weeks

- escape inhibition due to decrease in sodium/iodide transporter expression

Question 19

withdrawal from iodides will produce ___

Answer 19

thyrotoxicosis

Question 20

what drugs are useful for thyroid storms

Answer 20

Propylthiouracil

Iodides

Adjuncts - propranolol, atenolol, metoprolol

Question 21

what drugs can be useful for preoperative preparation for surgery due to its impact on hyperplastic glands - decreases vascularity, size and fragility

Answer 21

Iodides - potassium iodide and Lugol’s solution

Question 22

adverse effects of iodides

Answer 22

Cold sx - HA, sneezing, cough

Question 23

MOA of radioactive iodines in tx hyperthyroidism

Answer 23

beta rays destroy parenchymal cells f thyroid

gama rays can be used in detecting [RAI] remaining in thyroid glands

Question 24

why when treating hyperthyroidism with radioactive iodine do you often end up having to treat hypothyroidism

Answer 24

complete ablation can occur

Question 25

After radioactive iodine tx what should be used to control hyperthyroidism while waiting for effect

Answer 25

beta blockers iodide or antithyroid drug

Question 26

what is radioactive iodine therapy contraindicated for

Answer 26

pregnancy - concentrate in fetal thyroid

Question 27

what are the anion inhibitors in treating hyperthyroidism

Answer 27

perchlorate pertechnetate thiocyanate

Question 28

MOA of anion inhibitors

Answer 28

inhibit energy dependent uptake of iodide into the thryoid cell that is mediated by the sodium/iodide transporter

Question 29

Effects of anion inhibitors can be overcome by what?

Answer 29

large doses of iodide

Question 30

what type of hyperthyroidism do anion inhibitors treat

Answer 30

iodide-induced hyperthyroidism

Question 31

adverse effect of perchlorate (anion inhibitor)

Answer 31

aplastic anemai

Question 32

what is the major clinical use of propranolol in adjunct therapy

Answer 32

control tachycardia, HTN, and A fib also inhibits conversion of T4 to T3

Question 33

what adjunct can control tachycardia in asthmatics

Answer 33

diltiazem

Question 34

what adjunct increase T4 metabolism

Answer 34

barbituates

Question 35

what adjunct increases biliary T4 excretion

Answer 35

bile acid sequestrants

Question 36

which drug for hyperthyroidism can cause rash, nausea, GI distress, agranulocytosis, altered taste and smel

Answer 36

Methimazole (taste/smell in particular) propylthiouracil (severe hepatitis too_

Question 37

what hyperthyroidism drugs can cause a metallic taste, sore gums and teeth, skin lesions, hypersensitivity, angioedema, laryngeal edema, goiter if taken during pregnancy

Answer 37

Potassium iodide Lugol's solution