9 Factoids of Thyroid Hormone Physiology and Pharmacology Flashcards
What does the Thyroid hormone axis involve?
Stimulatory hypothalamic and anterior pituitary hormones.
What are the two thyroid hormones? Which is more active?
T3 and T4. T3 is more biologically active.
What thyroid hormone has a longer half life?
T4
What converts T4 to T3 in cells?
Deiodinases
What are Thyroid hormones required for?
Normal development of brain and for growth. Key homeostatic regulators of metabolism.
What does Hyposecretion of thyroid hormone cause?
Sloth-like sluggishness.
What does Hypersecretion of thyroid hormone cause?
Roadrunner-like symptoms.
What does clinical diagnosis of thyroid function include?
Resting levels of TSH and thyroid hormones.
What is usually used to treat hyposecretion?
Levothyroxine (third most prescribed generic drug in 2014, Synthroid was second most prescribed non-generic)
What drugs are frequently used to treat thyroid hormone hypersecretion due to Graves disease?
Thioamide drugs, Methimazole (Carbimazole) and Propylthiouracil.
What is the mechanism of Methimazole and PTU?
Inhibit Thyroid Peroxidase.
What does PTU also inhibit?
Iodinate I
What hyperthyroid drug is preferred?
Methimazole (Carbimazole)
What hyperthyroid drug is preferred in pregnancy?
PTU
What does radioactive iodine do? What is it used to treat?
It destroys the thyroid gland. It is used to treat hyperthyroidism that does not involve Graves’ disease.
