3) Thyroid - U5

Question 1

What is the class for Levothyroxine sodium (Synthroid)

Answer 1

Synthetic thyroid hormone (T4)

Question 2

What is the mechanism for Levothyroxine sodium (Synthroid)

Answer 2

Converted to T3 in liver; T3 binds toTR complex to influence gene expression

Question 3

What are the therapeutics for Levothyroxine sodium (Synthroid)

Answer 3

Drug of choice for hypothyroidism (longer half-life than T3)

Question 4

What are the important side effects for Levothyroxine sodium (Synthroid)

Answer 4

Hyperthyroidism: heart palpitations, nervousness, shaking, heat intolerance, weight loss

Question 5

What are the miscellaneous for Levothyroxine sodium (Synthroid)

Answer 5

Start low, go slow in patients with angina pectoris, CAD, and elderly; requires periodic monitoring and adjustment (especially during pregnancy); not effective in Chronic Fatigue Syndrome

Question 6

What is the class for Liothyronine sodium (Cytomel)

Answer 6

Synthetic thyroid hormone (T3)

Question 7

What is the mechanism for Liothyronine sodium (Cytomel)

Answer 7

T3 binds to TR complex in nucleus to influence gene expression

Question 8

What are the therapeutics for Liothyronine sodium (Cytomel)

Answer 8

Acute management of hypothyroidism (rapid effect); myxedema coma (IV formulation)

Question 9

What are the important side effects for Liothyronine sodium (Cytomel)

Answer 9

Hyperthyroidism: heart palpitations, nervousness, shaking, heat intolerance, weight loss

Question 10

What are the miscellaneous for Liothyronine sodium (Cytomel)

Answer 10

4X as potent as T4, but not desirable for chronic replacement (less stable, more costly, transient high levels)

Question 11

What is the class for Liotrix (Thyrolar)

Answer 11

Synthetic thyroid hormone (T4 & T3)

Question 12

What is the mechanism for Liotrix (Thyrolar)

Answer 12

Converted to T3 in liver; T3 binds toTR complex to influence gene expression

Question 13

What are the therapeutics for Liotrix (Thyrolar)

Answer 13

Thyroid hormone replacement therapy (4:1 mix of T4:T3; not used much)

Question 14

What are the important side effects for Liotrix (Thyrolar)

Answer 14

Hyperthyroidism: heart palpitations, nervousness, shaking, heat intolerance, weight loss

Question 15

What is the class for Propylthiouracil

Answer 15

Thioamide (thyroid peroxidase inhibitors)

Question 16

What is the mechanism for Propylthiouracil

Answer 16

Inhibit organification of iodide and coupling of iodotyrosine; also reduces peripheral deiodination of T4 to T3

Question 17

What are the therapeutics for Propylthiouracil

Answer 17

Hyperthyroidism; thyrotoxicosis (high dose); drug of choice for hyperthyroidism during pregnancy

Question 18

What are the important side effects for Propylthiouracil

Answer 18

Rare side effects: hepatitis, agranulocytosis (higher than methimazole), lupus-like syndrome

Question 19

What are the miscellaneous for Propylthiouracil

Answer 19

Discontinue and use radio-iodine if patient develops agranulocytosis or drug-induced lupus

Question 20

What is the class for Methimazole (Tapazole)

Answer 20

Thioamide (thyroid peroxidase inhibitors)

Question 21

What is the mechanism for Methimazole (Tapazole)

Answer 21

Inhibit organification of iodide and coupling of iodotyrosine; active metabolite of carbimazole; less effect on T4 to T3 conversion

Question 22

What are the therapeutics for Methimazole (Tapazole)

Answer 22

Hyperthyroidism; thyrotoxicosis (high dose)

Question 23

What are the important side effects for Methimazole (Tapazole)

Answer 23

Rare side effects: hepatitis, agranulocytosis (less than propylthiouracil), lupus-like syndrome

Question 24

What are the miscellaneous for Methimazole (Tapazole)

Answer 24

Discontinue and use radio-iodine if patient develops agranulocytosis or drug-induced lupus

Question 25

What is the class for Carbimazole (Neomercazole)

Answer 25

Thioamide (thyroid peroxidase inhibitors)

Question 26

What is the mechanism for Carbimazole (Neomercazole)

Answer 26

Prodrug converted to methimazole; Inhibits organification of iodide and coupling of iodotyrosine; less effect on T4 to T3 conversion

Question 27

What are the therapeutics for Carbimazole (Neomercazole)

Answer 27

Hyperthyroidism; thyrotoxicosis (high dose)

Question 28

What are the important side effects for Carbimazole (Neomercazole)

Answer 28

Rare side effects: hepatitis, agranulocytosis, lupus-like syndrome

Question 29

What are the miscellaneous for Carbimazole (Neomercazole)

Answer 29

Discontinue and use radio-iodine if patient develops agranulocytosis or drug-induced lupus; not available in US

Question 30

What is the class for Radioactive Iodine

Answer 30

Radioactive isotope

Question 31

What is the mechanism for Radioactive Iodine

Answer 31

Radioactive agent that emits beta particles and gamma rays that destroy thyroid cells

Question 32

What are the therapeutics for Radioactive Iodine

Answer 32

Treatment of choice for hyperthyroidism after antithyroid drug therapy; ablation after cancer

Question 33

What are the important side effects for Radioactive Iodine

Answer 33

Transient or permanent hypothyroidism; increases cancer risk

Question 34

What are the miscellaneous for Radioactive Iodine

Answer 34

Contraindicated in pregnant/breast feeding, patients under 10; monitor serum thyroid hormones post-treatment every 2-3 months for first year

Question 35

What is the class for ?-blockers

Answer 35

?-blockers

Question 36

What is the mechanism for ?-blockers

Answer 36

Reduce sympathetic tone

Question 37

What are the therapeutics for ?-blockers

Answer 37

Symptomatic treatment of hyperthyroidism (no effect on T3 synthesis)

Question 38

What are the miscellaneous for ?-blockers

Answer 38

Do not use on patient's at risk of heart failure! Discontinue use when patient returns to euthyuroid.