Week 8: Thyroid Agents

Question 1

Levothyroxine (Synthroid) MOA

Answer 1

• synthetic form of T4 - produces the same effects in the body as endogenous thyroid hormones - used to treat hypothyroidism

Question 2

Levothyroxine (Synthroid) ADRs

Answer 2

• anxiety
• palpitations
• generally not a lot of side effects if levels are maintained

Question 3

Levothyroxine contraindications

Answer 3

• caution in pts with CV disease (relative contraindications - start with a lower dose)
• avoid after recent MI

Question 4

Levothyroxine pt education

Answer 4

• take in the morning, preferably before breakfast on an empty stomach to increase absorption

Question 5

Methimazole (Tapazole) MOA

Answer 5

• inhibits the synthesis of thyroid hormones (mostly T4) by blocking the oxidation of iodine in the thyroid gland - 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 (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

• inhibits the synthesis of thyroid hormones by blocking the oxidation of iodine in the thyroid gland
• blocks conversion of T4 to T3 in the peripheral tissues
• used to treat the side effects of hyperthyroidism

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