Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
71 Cards in this Set
- Front
- Back
|
what is another name for T4?
|
thyroxine
|
|
|
what is another name for T3?
|
3,5,3' triiodothyronine
|
|
|
what buffers acute changes in thyroid levels?
|
1/3 of the body's T4 is in the liver and kidney
|
|
|
how much iodine to pregnant women need?
|
220microg
|
|
|
what can increase TBG levels?
|
estrogen in pregnancy or OCPs
|
|
|
what can decrease TBG levels? (3)
|
androgns
glucocorticoids malnutrition |
|
|
what 2 drugs decrease TBG binding?
|
phenytoin
salicylates |
|
|
what is the reference value for total T4?
|
5-11mg/dL
|
|
|
what is the reference value for total T3?
|
95-190ng/dL
|
|
|
what is the reference value for free T4?
|
9-24pmol/L
|
|
|
what 3 meds can impair thyroid synthesis?
|
lithium
thiocyanates amiodorone |
|
|
what is secondary/tertiary hypothyroidism?
|
deficiency of TSH/TRH
|
|
|
what is armour?
|
natural thyroid extract from pig/hog/sheep
|
|
|
what is the problem with armour?
|
it has an unpredictable T4:T3 ratio and too much T3 can cause toxicosis
|
|
|
what is an adverse reaction to armour?
|
HSR to foreign antigens
|
|
|
what are synthroid and unithroid examples of?
|
synthetic T4
|
|
|
what is levothyroxine sodium?
|
synthetic T4
|
|
|
what is the preferredd thyroid replacement?
|
T4
|
|
|
how is T4 administered?
|
orally
|
|
|
what can interfere with T4 absorption?
|
food, calcium, and antacids
|
|
|
how could phenytoin and salicylates have an effect on T4?
|
by decreasing binding, they disrupt it because T4 is highly protein bound
|
|
|
how long is the half life of T4?
|
8-9 days; clearance is slowed in hypothyroid patients
|
|
|
how is T4 metabolized and what can increase its metabolism?
|
CYP450
any drug that induces P450 will increase T4 clearance |
|
|
what 3 drugs increase CYP450?
|
phenytoin
rifampin phenobarbitol |
|
|
what 3 populations will require a lower starting dose of T4?
|
elderly
CAD longstanding hypothyroidism |
|
|
who will require a higher initial dose of T4?
|
pregnany hypothyroid patients
|
|
|
how often should TFTs be done once a euthyroid state is achieved in hypothyroidism?
|
every 3-6 months for the first year, yearly after that
|
|
|
what is the problem with a less severe overdose of T4?
|
the patient often doesn't know it's happening; insideous bone resoprtion leading to osteoporosis
|
|
|
what are cytomel and triostat examples of?
|
T3
|
|
|
what is liothyronine sodium?
|
synthetic T3
|
|
|
what is the problem with T3?
|
fast onset of action, half the dose needed, but more doses are needed
|
|
|
what is the treatment of choice of myxedemic coma?
|
triostat, the IV formulation of T3
|
|
|
who can T3 be used for?
|
patients who lack the ability to convert T4 to T3
|
|
|
what is liotrix?
|
T3-T4 combination
|
|
|
what is the problem with liotrix?
|
it is expensive
|
|
|
when should hypothyroid patients start seeing improvements?
|
within 2 weeks for symptoms, 6-8 weeks for TSH to normalize
|
|
|
what are 2 benign hyperthyroid tumors?
|
plummer's disease
toxic multinodular goiter |
|
|
what is the problem with pituitary tumors?
|
they do not respond to negative feedback
|
|
|
what 3 drugs can cause hyperthyroidism?
|
iodides
amiodorone lithium |
|
|
what is propranolol
|
an anti-thyroid drug used for symptomatic relief until thyrotoxicosis can be controlled
|
|
|
what is the MOA of propranolol?
|
the only beta blocker that can inhibit the conversion of T4 to T3 by inhibiting 5' deoiodinase
also reduces sympathetic response by blocking beta-adrenergic receptors |
|
|
what does propranolol effectively relieve? (4)
|
tachycardia
tremors anxiety sweating |
|
|
how soon does propranolol begin to work?
|
within 10 mins
|
|
|
what are thionamides used for?
|
long term hyperthyroid therapy
|
|
|
what are 2 thionamides?
|
methimazole
propylthiouracil |
|
|
what will thionamides have a minimal effect on?
|
exophthalmos
|
|
|
what is the MOA of thionamides?
|
reduce the synthesis of thyroid hormones by inhibiting thyroperoxidase which then prevents the oxidation of iodide to iodine as well as the coupling of iodine residues
|
|
|
what additional use does propylthiouracil have?
|
blocks the conversion of T4 to T3 in peripheral tissues by inhibiting 5'deiodinase
|
|
|
what will hionamides have no effect on?
|
the release of preformed hormones
|
|
|
how long do thionamides take to begin working and why?
|
delayed for a few weeks until existing stores of T4 and T4 are depleted
|
|
|
what are the 1/2 lives of thionamides?
|
PTU must be given 3-5x/day; methimazole has less frequent dosing
|
|
|
which thionamide has decreased fetal complications?
|
PTU
|
|
|
what drug is preferred in a thyroid storm?
|
PTU since it blocks T4-T3 conversion
|
|
|
what are 4 adverse effects of thiodamides?
|
HSR
joint pain fever edema |
|
|
when should thionamide patients seek treatment?
|
if they experience flu symptoms
|
|
|
what does PTU have a black box warning for?
|
liver dysfunction, though it is rare
|
|
|
how can KI be administered?
|
oral or IV
|
|
|
what are 3 uses of KI?
|
thyroid storm
preparation before ablation (by reducing the vascularity of the gland) protective against radioactive uptake |
|
|
how long does it take for thyrotoxicosis/gland size to decrease with KI?
|
2-3 days/10-14 days
|
|
|
what is MOA of KI?
|
sudden exposure to serum iodide inhibits organification of iodide and further synthesis of hormones
|
|
|
what are 4 adverse effects of KI?
|
sore throat
mucous membrane ulcers rashes metallic taste in mouth |
|
|
what are iopanoid acid and iopadate?
|
iodinated contrast agents
|
|
|
what are iodinated contrast agents used for?
|
effective temporary treatment of highly thyroitoxic patients
iotion for subacute thyroididis in patients intolerant to thionamides |
|
|
what is the MOA of iodinated contrast agents?
|
prevents the release of T4 and T3
inhibits the peripheral conversion of T4 to T3 |
|
|
what is I-131 the most effective treatment for? (4)
|
graves disease, patients with severe cardiac problems, adenomas, and those intolerant to thionamides
|
|
|
how is I-131 administered?
|
orally as a single dose
|
|
|
how is I-131 dosed?
|
5015 milicuries but must be calculated based on radioactive uptake and must pretreat with thionamides (especially in older patients)
|
|
|
how do you pretreat for I-131?
|
with thionamides, especially in older patients
|
|
|
what can I-131 also be used to treat? (3)
|
cases of relapse
test for thyroid function treat thyroid cancers |
|
|
who is I-131 contraindicated in?
|
pregnant and breast-feeding patients
|
|
|
what should be used prior to thyroid surgery? (2)
|
thionamides
KI |
