Thyroid Flashcards
Levothyroxine (T4/ synthroid)
Synthetic T4 for for hypothyroid
slow onset, takes 6-8 wks to reach a steady state
side: thyroxine toxicity
1 grain=
60 mg
Thyroxine toxicity ssx
palpitations, intolerance to heat, anxiety
Long term elevation of serum T4 may…
accelerate cardiac dz and osteoporosis
Thyroid replacement in addison’s
can be fatal if done without cortisol
Thyroid USP/Armour
porcine thyroid standardized to contain .2% iodine
1 grain has 38 mcg of T4 and 9 mcg of T3
sides: thyroxine tox
Liothyronine/cytomel
synthetic T3 for hypothyroid in pts who can’t take T4, also myxedema and wilson’s synd
100% oral absorption rapid onset.
peaks and troughs of T3 can lead to increased CAD or osteoporosis
Synthetic thyroid is dosed in ______ while natural is dosed in _____
synthetic mcg porcine mg (grain)
Dosing equivalents
60 mg armour=
100 mcg synthroid=
25 mcg cytomel
Methimazole/Tapazole
Thionamide for hyperthyroid
Inhibits conversion to organic iodine so thyroxine production is blocked. also inhibits coupling iodotyrosine
does not effect thyroglobulin already stored in the gland
sides: agranuloyctosis, rash, edema, arthralgias
Propylthiouracil PTU
Thionamide for hyperthyroid
blocks peripheral conversion of T4 to T3 in addition to typical thioamide MOA
Sides: AGRANULOCYTOSIS, rash, edema, arthralgias
What do you give during thyroid storm?
Beta blocker like propanalol for sx control
Iodine/SSKI
elemental iodine for hyperthyroid or thyroid storm
it inhibits the release of thyroxine
Super-saturated potassium iodide
Gland adapts to the dosing in 2-3 weeks and resumes its thyroxine secretion
Radioactive iodine
radioactive isotope for thyroid gland ablation
Usually takes weeks for destruction of thyroid gland
Results in hypothyroid state requiring lifelong hormone replacement.
May result in a few years of infertility
