Chapter 27: Thyroid Flashcards
Levothyroxine MOA
T4 replacement
Liothyronine MOA
T3 replacement
What is the drug of choice for hypothyroidism? Why?
levothyroxine because it has a longer elimination half life than T3
What is the drug of choice for a patient with myedema coma?
liothyronine (T3) because the onset of action is FASTER (clearly important for myxedema coma!!)
How do iodine uptake inhibitors work? Would you use these to treat hypo or hyperthyroidism?
These drugs compete with iodide for uptake INTO the thyroid gland follicular cells via the NA/I symporter –>
this would decrease the amount of iodide available for thyroid hormone synthesis
HYPERthyroidism
Percholate MOA?
iodine uptake inhibitor
What drug could you use as an alternative to surgery to treat hyperthyroidism?
Radioactive iodide
What is a risk/adverse effect of radioactive iodide?
Excess radiation can destroy the thyroid and then cause hypothyroidism
Also may worsen Graves’ ophthalmopathy
What drug would you administer prior to thyroid gland surgery to allow for easier excision?
Iodide in high concentrations - temporarily suppresses thyroid gland function
What is the drug of choice for Thyroid Storm or breast-feeding hyperthyroid patient….and what is its MOA?
PTU (propylthiouracil)
Inhibits thyroid peroxidase and the conversion of T4 to T3
What is the drug of choice for hyperthyroidism in a non-pregnant patient? MOA?
Methimazole
Inhibits thyroid peroxidase
When must you stop use of PTU and/or methimazole immediately?
Fever or sore throat develops (watch the WBCs)
What is the preferred B-adrenergic antagonist for treatment of thyroid storm? Why?
Esmolol
Rapid onset of action + short half life elimination
(Remember Esmolol like Eskimo and Thyroid Storm like Snow Storm)
Ipodate previous use?
Not available anymore…used to be used as a radiocontrast agest
