Thyroid drugs

Question 0

Liothyronine

Answer 0

synthetic T3 hormone, *short t1/2
Use: hypothyroidism replacement Tx, suppress thyroid nodule
SE if overdose: thyrotoxicosis, A-fib, tachycardia, osteopenia, weight loss, & heat intolerance

Question 1

Levothyroxine

Answer 1

synthetic T4 = T3 precursor,
Use: hypothyroidism replacement Tx
OR suppress non-auton. thyroid nodule (maybe, by lower TSH)
SE if overdose: thyrotoxicosis, A-fib, tachycardia, osteopenia, weight loss, & heat intolerance

Question 2

Methimazole

Answer 2

Thyroid peroxidase inhibitor
=> less Iodine to thyroglobulin = less T3 & T4 synth.
Uses: hyperthyroidism (1 mo.+ to take effect)
SE: agranulocytosis, hepatotoxicity, hypoprothrombinemia, rash, birth defects.

Question 3

Propylthiouracil (“PTU”)

Answer 3

thionamide,
–l thyroid peroxidase AND peripheral T4 -> T3 conversion
Uses: thyroid storm *limited bc SEs
SE: hepatotoxicity, birth defects (less than methimazole), agranulocytosis, hypoprothrombinemia