Week 8: Thyroid Agents

Question 1

Levothyroxine (Synthroid) MOA

Answer 1

• synthetic T4 (which is converted into active T3)

Question 2

Levothyroxine (Synthroid) ADRs

Answer 2

SX’S OF HYPERTHYROIDISM:

• anxiety
• palpitations
• insomnia
• weightloss

Question 3

Levothyroxine contraindications

Answer 3

• NO after recent MI
• caution in pts with CV disease (worsen sx’s)
• long term = decrease bone density
• caution in pts with adrenal insufficiency (GIVE glucocorticoids before starting this med)

Question 4

Levothyroxine pt education

Answer 4

• take in the morning, before breakfast empty stomach to increase absorption
• recheck levels at 6-8 weeks to reach steady state

Question 5

Methimazole (Tapazole) MOA

Answer 5

• inhibits the synthesis of TH (mostly T4) by blocking the oxidation of iodine in the thyroid gland (normally gland takes up iodine to make TH)
• does NOT inactivate T3/T4
• used to treat the side effects of hyperthyroidism

Question 6

Methimazole (Tapazole) ADRs

Answer 6

• urticaria (hives)

- agranulocytosis

Question 7

Methimazole (Tapazole) Contraindications

Answer 7

• Not safe in the 1st trimester of pregnancy; use PTU instead (ok for use in 2nd and 3rd trimester)

Question 8

Methimazole (Tapazole) patient education

Answer 8

• recommend that the patient not get pregnant while on these drugs

Question 9

Propylthiouracil (PTU) MOA

Answer 9

• blocks conversion of T4 to T3 / blocking oxidation of iodine
• used to treat the side effects of hyperthyroidism
• does NOT inactive T3/T4

Question 10

PTU ADRs

Answer 10

• urticaria
• agranulocytosis
• hepatitis (very hard on the liver)

Question 11

PTU Contraindications

Answer 11

• black box warning: hepatotoxicity

- PTU is safe in the 1st trimester of pregnancy