Unit 5-Thyroid Flashcards Preview

Pharmacology > Unit 5-Thyroid > Flashcards

Flashcards in Unit 5-Thyroid Deck (31):
1

Levothyroxine sodium

Drug class

Synthetic thyroid hormone (T4)

2

Levothyroxine sodium

Mechanism

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

3

Levothyroxine sodium

Uses

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

4

Levothyroxine sodium

Side effects

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

"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

5

Liothyronine sodium

Drug class

Synthetic thyroid hormone (T3)

6

Liothyronine sodium
Mechanism

T3 binds to TR complex in nucleus to influence gene expression

7

Liothyronine sodium

Uses

Acute management of hypothyroidism (rapid effect);

myxedema coma (IV formulation)

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

8

Liothyronine sodium

Side effects

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

 

9

Liotrix

Drug class

Synthetic thyroid hormone (T4 & T3)

10

Liotrix

Mechanism

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

11

Liotrix

Uses

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

12

Liotrix

Side effects

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

13

Propylthiouracil

Drug class

Thioamide (thyroid peroxidase inhibitors)

14

Propylthiouracil

Mechanism

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

15

Propylthiouracil

Uses

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

16

Propylthiouracil

Side effects

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

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

17

Methimazole

Drug class

Thioamide (thyroid peroxidase inhibitors)

18

Methimazole

Mechanism

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

19

Methimazole

Uses

Hyperthyroidism; thyrotoxicosis (high dose)

20

Methimazole

Side effects

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

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

Methimazole is a possible teratogen

21

Carbimazole

Drug class

Thioamide (thyroid peroxidase inhibitors)

22

Carbimazole

Mechanism

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

23

Carbimazole

Uses

Hyperthyroidism; thyrotoxicosis (high dose)

24

Carbimazole

Side effects

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

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

25

Radioactive Iodine

Drug class

Radioactive isotope

26

Radioactive Iodine

Mechanism

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

27

Radioactive Iodine

Uses

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

28

Radioactive Iodine

Side effects

Transient or permanent hypothyroidism; increases cancer risk

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

29

β-blockers

Mechanism

Reduce sympathetic tone

 

30

β-blockers

Uses

Symptomatic treatment of hyperthyroidism (no effect on T3 synthesis)

31

β-blockers

Side effects

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