CLASS NOTES Thyroid

Question 1

Tx of hypothyroidism

Answer 1

Levothyroxine, Liothyronine, Liotrix

Question 2

Mechanism of Action: Levothyroxine

Answer 2

Synthetic T4

Question 3

Levothyroxine vs Liothyronin

Answer 3

Longer half life, slower peak duration, eliminated more slowly

Question 4

SEs of Levothyroxine

Answer 4

Infants require more, angina pectoris requires lower initial dose

Question 5

Mechanism of action: Liothyronine

Answer 5

Synthetic T3; used in combo w/Levothyroxine; MORE POTENT. Less desirable for chronic use; tx for myxedema coma

Question 6

SEs of thyroid hormones

Answer 6

Hyperthyroidism symptoms

Question 7

Thioamides (3)

Answer 7

PTU, Methimazole, Carbimazole

Question 8

Mechanism of Action: Thioamides

Answer 8

Inhibits Thyroid peroxidase: inhibits organification of iodide and coupling of MIT/DIT

Question 9

Safer in pregnancy: PTU or Methimazole?

Answer 9

PTU

Question 10

Safer in agranulocytosis: PTU or Methimazole

Answer 10

Methimazole

Question 11

SE’s of Thioamides

Answer 11

Agranulocytsis, Hepatitis, Lupus-like syndrome

Question 12

Longer half life: PTU or Methimazole

Answer 12

Methimazole

Question 13

Faster excretion: PTU or Methimazole

Answer 13

PTU

Question 14

Less transplacental passage: PTU or Methimazole

Answer 14

PTU

Question 15

Lower concentration in breast milk: PTU or Methimazole

Answer 15

PTU

Question 16

Mechanism of Action: Radioactive I131 isotope

Answer 16

Destroys thyroid tissue

Question 17

Contraindications for I131

Answer 17

Pregnancy and breast feeding

Question 18

SE’s of I131

Answer 18

permanent hypothyroidism