TC5-D--Thyroid-Related Drugs

Question 1

Perchlorate

Answer 1

Anion Inhibitor (rarely used)
- competitively inhibits cellular uptake of iodide
SE: aplastic anemia

Question 2

Liotrix

Answer 2

T4 + T3 (4:1 ratio)

SE: hyperthyroid symptoms

Question 3

Lithium

Answer 3

Causes hypothyroidism

- inh thyroid hormone release

Question 4

PropylTHIOuracil (PTU)

Answer 4

Thioamide
- inh oxidation, organification, coupling steps of thyroid hormone synthesis
- inh peripheral deiodinase
SE: agranulocytosis

Question 5

Amiodarone

Answer 5

Causes hypothyroidism

- inh 5’-deiodinase

Question 6

Thiocyanate

Answer 6

Anion Inhibitor (rarely used)
- competitively inhibits cellular uptake of iodide

Question 7

Radioactive Iodide

Answer 7

Destroys thyroid tissue
Tx of thyrotoxicosis
SE: NO for pregnant or breastfeeding mothers

Question 8

Levothyroxine

Answer 8

T4
**DOC for hypothyroidism
Cheap, longer lasting, less potent
SE: hyperthyroid symptoms

Question 9

Rifampin

Answer 9

Causes hypothyroidism

- incr breakdown of thyroid hormone

Question 10

Liothyronine

Answer 10

T3
More expensive, shorter acting, more potent
SE: hyperthyroid symptoms

Question 11

Potassium Iodide

Answer 11

Inhibit thyroid hormone release via Wolff-Chaikoff effect

Question 12

Phenytoin

Answer 12

Causes hypothyroidism

- incr breakdown of thyroid hormone

Question 13

Phenobarbital

Answer 13

Causes hypothyroidism

- incr breakdown of thyroid hormone

Question 14

MeTHImazole

Answer 14

Thioamide
- inh oxidation, organification, coupling steps of thyroid hormone synthesis
SE: agranulocytosis, altered sense of smell