Drugs for Thyroid Disorders Flashcards
Anti-thyroid agents (4)
Radioactive iodine (I-)
Potassium iodine
Methimazole
Propylthiouracil (PTU)
In what condition would Propanolol be given for a thyroid disorder?
What is its MOA in this case?
To reduce HR and tremor during thyroid storm.
Inhibits conversion of T4 to T3 in peripheral tissues. It may help reverse reduced SVR.
What is the indication for Methimazole?
What is the MOA?
What are side effects? (2)
Which patients do you want to be cautious in giving this medicine?
Hyperthyroidism - Graves disease
Inhibits TPO enzyme (catalyzes a step in the synthesis of T3/4).
Agranulocytosis, WBC/RBC abnormalities.
Patients w/ liver disease (alcohol abuse, Hep, etc.)
When i Methimazole taken oftentimes?
Why?
Before surgery.
Lowers TH levels and minimizes the effects of thyroid manipulation.
What MOA is common to thioamide medicines (Methimazole, PTU, Carbimazole)?
Blocks iodide organification
What is the MOA of potassium iodide?
What can it be used for? (4)
It does NOT effect:
Blocks iodine uptake.
Treatment for hyperthyroidism, iodine deficiency, preparation for thyroidectomy, protection from radiation exposure.
Does not effect HR.
How does potassium iodide help protect from radiation?
Shrinks the thyroid and decreases TH production.
What are the indications for PTU? (4)
Graves disease
Toxic multinodular goiter (if intolerant to methimazole)
Preparation for thyroidectomy
Radioactive iodine therapy in patients who are intolerant of methimazole.
What is the MOA of PTU?
Inhibits synthesis of TH in hyperthyroidism and conversion of T4 to T3 in peripheral tissues.
It does not interfere w/ pre-existing TH.
What is the most sensitive screening test for hyperthyroidism and primary hypothyroidism?
TSH test
Levothyroxine is used to treat:
What is it?
How long does it take to reach its max effect?
What is the dosing based on?
TH deficiency
A form of T4 that is converted into T3
May take up to 6 wks
Dosing based on regular measurements of TSH and T4 levels in the patients blood
Side-effects of levothyroxine
Weight loss Heat intolerance Sweating Anxiety Insomnia Tremor Elevated HR
-anything that can happen in hyperthyroidism!
What is the major drug that impairs levothyroxine absorption?
Cholestryamine
Radioactive iodine therapy for thyroid cancer is contraindicated in who?
Pregnant women
Indications for Atenolol in thyroid disorders (2)
MOA
Graves disease
Thyroid storm
Membrane-stabilizing action and inhbits T4 to T3 conversion
