(Anti-) Thyroid Flashcards
concept: how do thyroid hormones increased BMR
increases BMR via Na/K ATPase = increases resp rate, increases temperature, increases O2 consumption
concept: effect of thyroid hormones on catecholamines
increases sympa activit = increase Co and HR
concept: effet of thyroid on brain
development
Where do you find 5’iodinase (not relaly important for this i dont think)
peripheral tissue liver kidney pituitary gland brain brown fat
describe receptors fo TRH – TSH – T3/T4
TRH - IP3
TSH - cAMP
T3/T4 - nuclear
(Words get bigger as you go furhter down chain)
What is levothyroxine
longet t1/2 T4
LEVO has four letters - thyroxine
What is Liothyronine
shorter t1/2 T3
LIO has three letters - thyronine
A/se of levothyroxine and liothyronine
tremors, tachycardia, arrhtymias, heat intolerace ie hyperthyroidism
effects of rifampin, phenobarbital and phenytoin on levels of T3 and T4
induce P450 blleeehhh so increased metabolism so less thyroid hormone
I say Queen Anne
you say laterla third eyeborw loss
Name the Thioamides
Propylthiouracil
methimazole
~*~MOA of propylthiouracil and methimazole
block idination of thyroglobulin and inhibit coupling reaction = reduced T3 and T4
inhibit thyroperoxidase so decreased new T3 adn new T4 but not preformed.
Preferred drug in thyroid storm and why please
propylthiouracil
bc
1) inhibits 5-deiodinase – decreased conversion from T4 to T3
(methimazole does not do this)
~*~A/se of thiamide, propylthiouracil
propylthiouracil = rash, agranulocytosis, aplastic anemia, hepatotoxicity, vasculitis
~*~A/se of thiamide, metimazole
less severe, and therefore more preferred in clinical setting
POSSIBLE TERATOGEN
WOLFF CHAIKOFF!!
iodide at high levels inhibit organification and release = lower levels, but this wanes at 10-14 days and therefore is not used for long term treatment
Used of Iodine and Iodide salts
decreases vascularity and size of gland – used before surgery before excision
and tyrotoxicosis cirisis with propylthiouracil and beta blockers
Three drugs used in thyrotoxic crissi
propylthiouracil
Iodine/Iodide salts
beta blockers
Describe the prepartions available for iodine and iodide salts
1) lugol solution - iodine and potassium iodide
2) saturated solution of potassium iodide only
THyroid storm again. the lecture just keeps adding drugs
propylthiouracil
iodine/iodide salts
beta blcokers - nadolol, atenolol
MOA propanolol
non specific bb
**prevents conversion of T4 to T3
MOA esmolol
short acting BB
control intraoperative thyroid storm
DOC at intraoperative thyroid storm
esmolol
DOC at thyroid storm in patients with asthma
diltiazem - calcium channel blocker
SHARK flashback – can complicate diabetic treatment by causeing hyperglycemia in diabetics
What do you give to prevent peripheral conversion of T4 to T3 in thyroid storm
holy monkeys thyroid storm
propylthiouracil IV sodium iodine glucocorticoids bb diatrizoate and iohexol
MOA of diatrizoate and iohexol
iodinated radiocontrast medial that suupresses action fo 5’iodinase - no conversion of T4 to T3
use at tyrotoxicosis to decreased T3 concentraiton
Perchlorate
Thiocyanate
Pertechenetate
MOA
inhibit iodide concentation in gland by blockign transportation
Why do we care about amiodarone
coat of many colours
structural similarity with thyroxine
a) iodine associated hyperthyroidism
b) autoimmune mediated inflammatory version <– treat with steroids
c) hypothyroidism due to blockade of T4 to T3
How to treat iodine associated hyperthyroidism caused by amiodarne
thiamides - propylthiouracil and metimazole
Lithium affect on thyroid style
inhibits release of hormones (hypothyroidism) and causes thyroid enlargement
Name some drugs that provoke autoimmune or destructive inflammatory thyroiditis to induce hypothyroidism
a) amiodarone
b) IFNalpa
c) IL-2
d) Litihium
What do these drugs have in common
a) amiodarone
b) IFNa
c) IL-2
d) Lithium
all provoke autoimmune or destructive inflammatory thyroidiits resulting in hypothyroidism
SHARK: Name three drugs that inhibit conversion of T4 to T3
corticosteroids
propranolol
amiodarone
Name some goitrogens
cabbage - thiocyantae (prevents uptake of I)
cassava - carbs _ thioc;yanate (prevents uptake of I with perchlorate and pertechetol)
