Thyroid Drugs

Question 1

Agents to treat Hypothyroidism

Answer 1

Desiccated thyroid, Levothyroxine, Liothyryonine

Question 2

Desiccated Thyroid (Armour Thyroid)

Answer 2

contains T3, T4, derived from pork thyroid glands, antigenic, and has highly variable biologic activity

Question 3

Levothyroxine (Synthroid)

Answer 3

T4 DRUG OF CHOICE to treat hypothyroid.

Longer duration and lower cost than T3

Question 4

Liothyronine (Cytomel)

Answer 4

T3, quicker onset of action and better absorption

Question 5

Contraindications of Hypothyroid medication?

Answer 5

Acute MI

Question 6

Drug interactions of hypothyroid medication?

Answer 6

increase anticoagulant effects

Reduce effects of digitalis

Question 7

Antithyroid Agents

Answer 7

Thioureylenes, Propylthiouracil, Methimazole (Tapazole)

Question 8

MOA of Antithyroid Agents

Answer 8

Interfere with iodination of tyrosyl residues in thyroglobulin and inhibit coupling reaction by blocking thyroid peroxidase enzymes

Question 9

What does Propylthiouracil (PTU) do?

Answer 9

Blocks peripheral conversation of T4 to T3

Question 10

What difference does Methimazole have?

Answer 10

Longer half life, once a day dosing

Question 11

Side effects of Antithyroid Agents

Answer 11

Agranulocytosis and bone marrow aplasia
Cross PLACENTA and secreted in mother’s milk
PTU- FATAL LIVER DISEASE- BLACK BOX

Question 12

Radioactive Iodine (131 I)

Answer 12

B- rays destroy parenchymal cells of thyroid with little damage to other tissue, considered DOC
Causes delayed hypothyroidism in about 50% pt
Can cause chromosomal aberrations, avoid in young, pregnant

Question 13

What is Thyroid Storm?

Answer 13

Extreme hyperthyroidism- fever, tachycardia, nausea, vomiting, confusion, coma, death