Thyroid/Parathyroid 2 Flashcards
increases in doses made on monthly basis
greater hepaotoxicity than MMI
which drug?
propothyrouracil (PTU)
possible teratogenic effects
more potent than PTU
changes in dose made on monthly basis
which drug?
Methimazole (MMI)
PK of PTU and MMI
peak serum concentration is 1 hr after digestion (well absorbed in GI tract)
minimal urinary excretion (less for MMI)
how long does it take sxs of PTU and MMI to diminish & thyroid hormone levels to return to normal?
4-8 wks
ADEs of what?
pruiritic maculopapular rash
benign transient leukopenia
agranulocytosis
hepatotoxicity
arthralgias & lupus-like syndrome
PTU & MMI
What drug do you give to pregnant pts w/hyperthyroidism and why?
PTU in 1st trimester: use lowest dose to maintain maternal T4 levels in high-normal range
teratogenic effects of MMI outweigh hepatotoxic effects of PTU
dosage unikely to produce fetal goiter
PTU <200mg
best tx for toxic nodules and toxic multinodular goiter
radioactive iodine (RAI)
RAI pros
cure hyperthyroidism
RAI cons
- permanent hypothyporidism (inevitable)
- defer pregnancy 6-12 months: no breast feeding
What would you use as an adjunct to RAI?
Potassium iodide (SSKI) should be added 3-7 days after RAI tx so radioactive thyroid can concentrate in the thyroid
When should Potassium iodide (SSKI) be administered in regards to surgery?
give 7-14 days before surgery
what medication is given for sx relief?
adrenergic blockers: propanolol
alt: clonidine, diltiazem
how does propanolol help hyperthyroidism?
decreases palpitations, anxiety, tremor, and heat intolerance
Used as adjunct to antithyroid
primary tx for thyrotoxicosis a/w thyroiditis
propanolol
CI of propanolol
dont use in pts with decompensated HF
sinus bradycardia
pts on MAOI or TCAs
spontaneous hypoglycemia
ADEs of Propanolol
N/V
anxiety
insomnia
Iodide MOA
graves: blocks thyroid hoemone release
inhibits biosynthesis: interferes w/intrathyroidal iodide utilization
decreased size/vascularity of gland
how long does it take for sx improvement when using iodides?
2-7 days
Concerning Iodides:
T/F: Even though there is a decrease in T4/T3 release, hormone synthesis continues at an accelerated rate, resulting in a gland rich in stored hormones.
True
T/F: normal and hyperfunctioning thyroid escapes inhibitory effect in 1-2 weeks.
True
ADEs of Iodides
salivary gland swelling
“iodism” –>burning mouth/throat, sore teeth & gums
gynecomastia
what is thyroid storm
thyrotoxicosis so severe it causes decompensation
what meds do you use for thyroid storm
- PTU or MMI
- sodium iodide
- lugols solution
- propanolol
- corticosteroids: dexamethasone, prednisone, methylprednisone or hydrocortisone
sx of hypoparathyroidism
usually asx
acute: tetany
chronic: lethargy, anxiety/depression, cataracts, coarse skin
systems affected: endocrine/metabolic, MSK, CNS, opthomalogic, renal
what does disrupted PTH action result in
hypocalcemia
hyperphosphatemia
hypercalciuria
what is crucial for PTH secretion and activation of PTH receptor
magnesium
Tx for hypoparathyroidism
maintain serum Ca 8-8.5
oral Ca carbonate (ca salts) 1-3g a day
calcitriol
maintain serum Mg
Phosphate binders
thiazide diuretics + low salt diet
what should you use instead for geriatric pts w/ hypoparathyroidism on a PPI or those who have constipation on oral calcium carbonate (calcium salts)?
calcium citrate
what does the use of thiazide + low-salt diet prevent?
hypercalciuria
nephrocalcinosis
nephrolithiasis
monitoring goals for hypoparathyroidism
Ca 8-8.5 (if Ca< 8, tx if asx)
24 hr urine Ca <300mg
Ca-phosphate <55mg
Measure Ca, Phosphate, Mg, Cr weekly-monlthy during initial management
Lab results for primary HPT
PTH > 3 (high)
lab results for non-PTH-mediatedhypercalcemia
PTH < 3.0 (low)
Tx of Primary HPT
operative management is curative
tx of pts with primary HPT awaiting surgery
bisphosphonates (alendronate) **avoid in kidney dz**
SERM (raloxifene)
secondary HPT tx
replace Ca
vit D analogs (paricalcitol & calcitriol)
phosphorous binding agents (sevelamer)
calcimimetic (cinacalcet)
