Thyroid Pharmacology Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is the T4 thyroid hormone replacement rpeparation?

A

Levothyroxine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the T3 thyroid hormone replacement preparation?

A

Liothyronine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are Thioamines used for?

A

for the treatment of hyperthyroidism

and to prepare for thyroid surgery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the 4 examples of thioamines?

A

methimazole

Carbimazole (which metabolizes to methiomazole)

Propylthiouracil

Potassium Iodide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What did Japanese citizens use to counter radioactive potential exposure to iodine after the Fukushima Daiichi nuclear disaster?

A

potassium iodide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How is levothyroxine typically dosed?

A

once daily

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the half life for levothyroxine?

A

about 7 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are some things that will decrease the absorption of levothyrosine?

A

iron
calcium
alcohol
soy products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Should you lower or increase the dose of levothyroxine during pregnancy?

A

need to increase is by 30-50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the adverse effects of iatrogenic hyperthyroidism (if you take too much)?

A
palpitations
tremors
anxiety
weight loss
tachycardia
increased # of bowel movements
arrhythmia/angina/MI in those with heart disease

atrial fibrillation in the elderly
bone loss with chronic oversupplementation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which ones has greater potency - Levothyroxin or Liothyronine?

A

liothyronine (T3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

So when is liothyronin most useful?

A

when a quick onset is desirable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the half-life of liothyronine though?

A

only about 2 days - shroter than levothyroxine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What drug class inhibits thyroid hormone synthesis?

A

the thioamides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Again, what are the three major thioamindes?

A

methimazole
carbimazole
propylthiouracil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What enzyme do the thioamides inhibit?

A

thyroid peroxidase

17
Q

Propylthiouracil also inhibits a second enzyme, which is?

A

Deiodinase 1

18
Q

What is the duration of action for PTU? How about methimazole/

A

12 hours for PTU and 24 hours for methimazole

19
Q

How long does it take for these thioamides to take effect?

A

2 weeks

20
Q

Thioamides are the first line of attack in what disease?

A

Graves

21
Q

What are the three main uses for iodine in the context of hyperthyroidism?

A
  1. preparation for thyroidectomy
  2. treat thyroid storm
  3. protection from radioactive iodin
22
Q

Why do high concentrations of iodine help in hyperthyroidism?

A

because high concentrations inhibit almost all aspects of iodine metabolism, including thyrport, synthesis of iodotryrosines and iodytronines and release of thyroid hormones

23
Q

True or false: “escape” from iodine treatment can occur.

A

true

24
Q

What are the major side effects of iodine?

A

allergic reactions
sore teeth and gums
excess salivation

25
Q

What are the two forms of radioactive iodine we use?

A

123-I

131-I

26
Q

What is 123-I used for?

A

to scan the thyroid in nuclear imaging studies

27
Q

What do we use 131-I for?

A

to destroy the thyroid in cases of hyperthyroidism not caused by Graves

28
Q

131-I is painless, easy to administer, cheap and effective. But what’s the disadvantage?

A

often too much destructione

29
Q

How do you need to manage a person after 131-I treatment/

A

need to supplement thyroid hormones

30
Q

About how long do patients with GRaves disease need to be on antithyroid drugs?

A

usually a course of 12-18 months

but note: recurrence rates of ATD are high

31
Q

What is the percentage of Graves patients that have a permanent remission after ATD discontinuation?

A

30-50% in adults

30% in children

32
Q

What is the FDA warning on propylthiouracil?

A

there is risk of serious liver injury including liver failure and death

monitor closely during the first six months after initiating therapy and so opt for methimazole instead!

33
Q

What is the rare side effect that has been reported with methimazole during pregnancy? So what does this mean in deciding what drug to give?

A

rare cases of emryopathies like aplasia cutis have been reported with methimazle during pregnancy, but no cases reported with propylthiouracil use

so PTU might be more appropriate for patients with Graves disease whoa re in their first trimester of pregnancy