Exam 3 likely questions for exam Flashcards
what is the drug of choice for thyroid hormone replacement?
levothyroxine/synthroid
besides hypothyroidism what else is levothyroxine indicated for?
For TSH suppression in select nodules and thyroid cancers
what does long term elevation of T4 (from high dose replacement or hyperthyroidism) increase the risk of?
may accelerate cardiac disease and osteoporosis
What is important about treating Addison’s disease patients with hypothyroidism?
Thyroid hormone replacement must be done with cortisol, otherwise it is FATAL!
What are the equivalent doses of thyroid hormone? (synthroid, armour, and cytomel)
100 mcg of T4 (Synthroid) ~ =
60 mg Thyroid USP (Armour) ~ =
25 mcg of T3 (Cytomel)
the most common cause of hyperthyroidism is called?
Grave’s Disease (autoimmune)– antibodies stimulate TSH receptors
hyperthyroidism due to graves disease is usually accompanied by what?
goiter and exophthalmos
also: pretibial myxedema
what is the definitive tx for hyperthyroidism?
surgical removal or radioactive ablation of thyroid gland
How are the MOA of methimazole and PTU similar? different?
they both inhibit the transformation of inorganic iodine to organic iodine blocking the production of thyroxine and inhibiting the formation of T3 and T4.
**PTU blocks the peripheral conversion of T4 to T3 while methimazole has minimal effects.
what is the most feared side effect of methimazole or PTU?
Agranulocytosis
what category is PTU?
Category D, considered safer than methimazole (and used in pregnancy only when benefit out weighs risk)
Does propanolol affect the thyroid gland?
No, it mitigates sxs such as anxiety, tremors, palpitations, etc.
MOA of iodine/SSKI?
large doses of iodine inhibit the release of thyroxine from thyroid gland
how long is iodine/SSKI effective for?
2-3 weeks as the thyroid gland adapts and resumes secretion of thyroxine.
what category drug is radioactive iodine (131 I)
Category X, given during pregnancy can irreversibly damage the fetal thyroid tissue. When given to a nursing mother, radioactive iodine can reach a baby through the breast milk
How are men effected by radioactive iodine?
Men who receive RAI treatment for thyroid cancer may have decreased sperm counts and temporary infertility for periods of roughly two year
what is the most severe manifestation of hyperthyroidism?
Thyroid storm
what are some signs of thyroid storm?
high fever, irritability, delirium, vomiting, diarrhea, dehydration, hypotension and vascular collapse.
(Coma and death may occur…too late for signs then!)
