Thyroid and Antithyroid drug list Flashcards
L-T4
Levothyroxine
L-T3
liothyronine sodium
mixture of L-T3 and L-T4
liotrix
What are the anti-thryoid drugs?
propylthiouracil, methimazole, carbimazole
3 proteins that bind T3 and T4
albumin, TBG, TBPA
What happens to the ratio of T4:T3 in iodine deficiency?
Goes from 4:1 to 1:3
T or F. IN the first trimester of pregnancy, the fetus relies on TH from maternal circulation.
T
How are T3 and T4 metabolized
in liver through glucuronide and sulfate conjugation. Enterohepatic circulation
____ transports T4 in CSF.
TTR
Describe the binding of TBG
The major carrier, T4 tighter.
Describe the binding of TTR (TGBPA)
Gets higher affinity after binding first T4
*Figure out what slide 50 means about “higher level in blood for TTR than TBG”
Because TTR has higher affinity (lower Ka)?
Describe binding of albumin
Both T3 and T4
What are immediated, later, and last effects of TSH
Immediate: increased secretion
Later: iodide uptake, hormone synthesis, proteolysis
Last: hypertrophy and hyperplasia
____ is the preferred method of preventing iodine deficiency.
Iodized salt
TH act primarily through binding ____ receptors.
nuclear
MOA of T3 and T4 at nucleus
T3: regulates transcription. Binds TRB1 and 2, TRa1. Binds mitochondrial membrane and activates enzymes.
T4: can bind same receptors but not regulate transription
What drugs are used in hyperthyroidism?
thioureylenes(methimazole, PTU), carbimazole,
MOA of PTU
inhibits peripheral conversion of T4 to T3, inhibit iodine organification
MOA of thioureylenes and carbimazole
inhibit iodine organification
Describe methimazole
10x more potent than PTU, crosses placenta and gets concentrated in fetal thyroid
What anti-thyroid drug is used in pregnant pt?
PTU- less placentral transfer and excretion in milk
Adverse reactions to PTU
minimal, agranulocytosis, skin rash
ADE of iodinated contrast medium
Euthyroid–> hyperthyroidism
Hyperthyroid–> thyroid storm
What do large doses of iodine do?
block release of TH, tx thyroid storm, decrease size and vascularity of gland–> preop!
What is radioactive iondine?
oral, concentrated in thryoid, B radiation will destroy parenchymal cells, no evidence of damage to other tissues,
Who can use radioactive iodine?
adults >35, NOT in women of child bearing age
