Thyroid Pharmacology Flashcards
Thyroid hormones are best absorbed by the _____________.
ileum
Levothyroxine should be taken on a(n) ______________.
empty stomach
What impairs the absorption of levothyroxine?
Metal cations
Ciprofloxacin
The activating deiodinases are inhibited by _______________.
glucocorticoids, beta-blockers, amiodarone, caloric deprivation, and chronic illness
T4 requires ___________ to become effective.
6-8 weeks
Be careful giving T4 to those with ____________.
underlying cardiac illness
Why is it necessary to give increased doses of T4 to pregnant women?
Because the excess estrogen induces greater thyroid-binding globulin and excess metabolism of thyroxine
If you give a large dose of thyroxine to someone having a thyroid crisis, what else do you need to give?
Corticosteroids to prevent adrenal insufficiency
There is no evidence to support that the brand name of thyroxine ____________.
is superior
The pharmaceutic name for triiodothyronine is ____________.
liothyroxine
Which has better bioavailability, T3 or T4?
T3
Why is T3 more potent than T4?
It has a higher affinity for thyroid-hormone receptors.
How do methimazole and propylthiouracil work?
They inhibit thyroid peroxidase, specifically where it organifies iodide.
What can lead to permanent destruction of the thyroid?
I(131) –radioactive iodide
Which thyroid peroxidase inhibitor is best for pregnant women?
Propylthiouracil (Pregnancy = Propylthiouracil)
Doctors occasionally give __________ before administering radioactive iodine.
TSH
What causes unbinding from TBG?
Phenytoin
Carbamazepine
Furosemide
Glucocorticoids
What drugs can cause euthyroid sick syndrome?
Beta-blockers
Amiodarone
PTU
Glucocorticoids
The other name for T3 is _____________.
liothyronine
Methimazole is generally the preferred medication because of lack of ______________.
hepatotoxicity, efficacy at lower doses, and once-daily dosing
_________, which rises in pregnancy, stimulates production of TBG.
Estrogen
Remember that methimazoles and thionamides are only for hyperthyroidisms from excess _____________.
production, not release
The most dangerous side effect of methimazole and PTU is _____________.
agranulocytosis
What is SSKI?
Super-saturated potassium iodide
This is only used in thyroid storms.
