Thyroid Pharm

Question 1

Levothyroxine

Answer 1

Synthroid
Thyroid hormone replacement (T4)
Takes a long time to reach steady state - pt won’t feel better for ~6 weeks, shouldn’t recheck TSH levels until then

Question 2

radioactive iodine

Answer 2

for hyperthyroidism: radioactive iodine is taken into thyroid cells, goes into colloid, used in iodination and coupling of the tyrosine residue, emits beta particles –> kills the thyroid follicle cells over time –> thyroid stops making T4

Question 3

methimazole

Answer 3

northyx
inhibits thyroid peroxidase
won’t work immediately, b/c takes a while to wash out the previously high levels of T4
always use this over PTU except in 1st trimester of pregnancy (can cause fetal malformation - rare)

Question 4

propylthiouracil (PTU)

Answer 4

inhibits thyroid peroxidase + inhibits conversion of T4 to T3
won’t work immediately, b/c takes a while to wash out the previously high levels of T4
SE: severe liver injury, agranulocytosis
can be used for rapid control of severe hyperthyroidism (b/c effects on T4–>T3 in periphery)
preferred in 1st trimester of pregnancy