Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharm block 4 > Thyroid Drugs > Flashcards

Thyroid Drugs Flashcards

1
Q

What are the steps of thyroid hormone synthesis?

A
  1. Uptake of iodine
  2. Iodine organification: oxidized by peroxidase, and iodinates tyrosine
  3. Coupling of MIT & DIT
  4. Secretion of thyroid hormones
  5. Conversion of T4 to T3 (periphreal conversion)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is biologically available for tissue use?

A

Free thyroid hormone (T3); rest are bound.

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

What are the differences of T3 and T4?

A
  1. T4: Combination of two DIT molecules, less potent, 75% protein bound, converted to T3 in periphreal tissues, liver, and kidney. 0.04% free form.
  2. T3: One MIT and one DIT molecule, more potent, 25% bound, binds actively to nuclear receptor. 0.4% free form.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a lack of thyroid hormone in fetal life known as?

A

Cretinism.

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

What are symptoms of hypothyroidism?

A

Fatigue, cold intolerance, weight gain despite lack of appetite, irregular menses, non-pitting edema, high cholestrol.

Etiology: Hashimoto’s, drugs or radiation exposure, or pituitary tumor

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

What treats hypothyroidism?

A

Levothyroxine; consistent potency with long duration , in emergencies Liothyronine sodium.

This also prevents mental retardations in infants with thyroid deficiency

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

What are some ADR of Levothyroxine (T4)?

A

Tachycardia, heat intolerance, and tremors

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

What are indications and ADRs of Liothyronine Sodium (T3)?

A

Myexdema coma (medical emergency with hypothermia, respiratory depression, and loss of conciousness)

ADR: More cardiotoxic than Levothyroxine, do not use in patients with heart disease.

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

What are symptoms of hyperthyroidism?

A

Excitability, intolerance to heat, excessive sweating, mild to extreme weight loss, muscle weakness, extreme fatigue with inability to sleep, EXOPTHALMUS,

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

View table on Slide 19

A

Has a star dawg

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

What are thioamidines, and MOA?

A

Propothyiouracil (PTU), Methimazole, Carbimazole; treat hyperthyroidism.

MOA: Inhibit peroxidase enzyme preventing iodination and coupling, which inhibits synthesis of thyroid hormones

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

What are some ADRs of thioamidines?

A

Urtictrical papular rash and agranulocytosis.

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

What are some ADRs of Methimazole itself?

A

Cholestatic dysfunction, teratogenic but used in 2nd or 3rd trimester to avoid PTU liver toxicity

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

What are some ADRs of PTU itself?

A

Liver failure, not used in children unless Methimazole allergy, teratogenic as well but preferred in 1st trimester due to excessive protein binding

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

What are some uses of thioamidines?

A
  1. Graves disease
  2. Conjunction with radioactive iodine
  3. Preop preperation of the thyroid gland
  4. Thyrotoxic crisis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are ionic inhibitors, and name some:

A

Competivitely inhibit NIS, but unpredictable effects.

Thiocynate –> Inhibit organification of Iodine
Perchlorate –> 10x more effective than thiocynate
Flouroborate –> Same effect as Perchlorate

17
Q

What is an ADR of Perchlorate?

A

Fatal aplastic anemia

18
Q

What is the use of ionic inhibitors?

A

Treat iodine induced hyperthyroidism like Amiodarone-induced thyrotoxicosis.

19
Q

What are the iodides, what are they composed of, and MOA?

A

Lugol’s Solution –> 5% iodine, 10% potassium iodine, 8mg of iodine per drop
Saturated Solution of Potassium Iodide (KISS) –> 50mg per drop
Potassium Iodide

MOA: Limit own transport, inhibition of synthesis of iodotyrosine, inhibit release of thyroid hormone, and reduce vascularity/size.

20
Q

What are the uses of the iodides?

A

Preop preparation of thyroid gland, thyrotoxic crisis, radioactive iodine fallout.

Response within 2-7 days, maximal effect 10-15, vascularity reduced, gland becomes firmer!

21
Q

What are some ADRs of iodides?

A

Marked sensitivity to iodine (causing angioedema, laryngeal edema, serum-sickness hypersensitivity, thrombotic thrombocytopenia purpura)

Iodism (chronic intoxication with iodine, causing brassy taste with burning in mouth and throat, increase salivation sneezing, and irritation of the eyes, pulmonary edema, and parotid/submaxillary gland enlargement)

In pregnancy, crosses placenta and causes fetal goiter.

22
Q

What is the MOA of radioactive iodine?

A

Get trapped in thyroid gland, incorporate into the amino acids, deposit in the colloid, and the beta-particles act on parenchymal cells of the thyroid ablating the thyroid tissue.

23
Q

What are uses of radioactive iodine?

A

Graves Disease (especially in pts w/ heart disease, after making them euthyroid), toxic nodular goiter.

24
Q

What are contraindications of radioactive iodine?

A

Pregnancy & lactation, Graves opthalmopathy

25
Q

What are disadvantages of radioactive iodine?

A

Increase delayed hypothyroidism, Increase stomach, kidney, and breast cancer, increase radiation thyroiditis.

26
Q

How should radioactive iodine be administered?

A

Discontinue antithyroid drugs for a week before, and resume 3 days after taking radioactive iodine tablet because of efficacy, and avoid iodides that are competitive for reuptake.

27
Q

Why are anti-thyroid drugs used before surgery?

A

Damage to the thyroid gland causes outpouring of stored colloid thyroxine which worsens thyrotoxic symptoms.

28
Q

What are some adjunct therapies for hyperthyroidism?

A
  1. Beta adrenergic receptor antagonists (Propanolol): Antagonize the sympathetic effects of thyrotoxicosis
  2. Ca+ channel blockers (Diltiazam): To control tachycardias and decrease SVT tachyarrhythmias.
  3. Dexamethosone/Iopanoic Acid & Sodium Ipodate: Inhibit periphreal conversion of T4 to T3
  4. Cholestyramine: Block enterohepatic circulation of iodothyromine
  5. Rituximab: Prolong remission of Graves Disease
29
Q

Name ways a beta blocker can help in a hyperthyroidism?

A

Must be without intrinsic sympathomimetic activity; inhibit T4 to T3 conversion.

NOTE: Sodolol and Nadolol don’t enter CNS, so don’t inhibit conversion, Propranolol is preferred due to lipid solubility

30
Q

What is thyroid storm and what are the supportative measures?

A

Stress, trauma, surgery, infection, etc. cause exaggerated thyrotoxicosis.

Give IV fluids, antipyretics, cooling blanket, and sedate.

31
Q

What drugs are used to treat thyroid storm?

A
  1. PTU (inhibiting periphreal conversion)
  2. Beta adrenergic blockers (treat HTN and increased HR)
  3. Hydrocortisone (prevent shock)
  4. Oral Iodides
  5. Tx of underlying precipitating illness

Pharm block 4 (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions