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7 Cards in this Set
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Levothyroxine (T4)
liothyronine (T3) |
thyroid hormone replacements
replace missing endogenous thyroid hormone with exogenous thyroid hormone |
chlestyramine and sodium polystyrene sulfonate decrease absorption of synthetic thyroid hormone, because of longer half life T4 preferred for treatment, T3 may be preferred in myxedema coma due to faster onset of action
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perchlorate
thiocyanate pertechentate |
iodide uptake inhibitors
compete with iodide for uptake into thyroid gland follicular cells via Na+/I- symporter, thereby decreasing intrathyroidal supply of iodide available for thyroid hormone synthesis |
clinical use in hyperthyroidism limited due to risk of developing aplastic anemia, frequently used as radiocontrast agents
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131 I - (radioactive iodide)
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inhibitors of organification and thyroid hormone release
strongly emits beta particles that are toxic to thyroid follicular cells |
alternative to surgery in treatment of hyperthyroidism
excess radiation can destroy thyroid, thereby causing hypothyroidism |
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iodide (high concentrations)
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inhibits iodide uptake and organification via Wolff-Chaikoff effect
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used for temporary suppression of thyroid gland function, also used before thyroid gland surgery to allow technically easier excision
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propylthiouracil (PTU)
methimazole |
PTU inhibits thyroid peroxidase and conversion of T4 -> T3
methimazole inhibits thyroid peroxidase |
methimazole generally preferred in treatment of hyperthyoidism due to lower incidence of serious adverse effects, PTU preferred agent in thyroid storm due to additional peripheral inhibition of T4 to T3 conversion
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B blockers
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inhibitors of peripheral thyroid hormone metabolism
blocks 5; deiodinase thereby inhibiting T4 to T3 conversion |
Sympatholytic effect of beta blockers more important in treating symptoms of hyperthyroidism than minor effect of these drugs on 5'deiodinase, esmolol preferred B adrenergic antagonist for treatment of thyroid storm bc of rapid onset in action and rapid elim half life
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Ipodate
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inhibitors of peripheral thyroid hormone metabolism
blocks 5; deiodinase thereby inhibiting T4 to T3 conversion |
formerly used as radiocontrast agent
no longer commercially available |
