Thyroid and calcium homeostasis Flashcards
What medications can you prescribe for hypothyroidism
Levothyroxine (T4)
Liothyrine (T3)
Liotrix (T3+T4)
What are the goals of treating hypothyroidism
provide resolution in patients symptoms
Achieve normalization of serum thyrotropin (TSH) w/ improvement in thyroid hormone concentrations
avoid over treatment - especially in elderly
What may decrease absorption of T4
Aluminum and magnesium containing antacids
What is the PK of T4
Metabolized in the liver
eliminated in bile
half life 7 days
deiodinated in patients tissue
What is the PK of T3
Oral
short half life
metabolized by liver
eliminated in bile
What is important to teach patients when prescribing T4
Needs to be on an empty stomach
What are some adverse effects of T3
Increased risk of cariotoxicity
transient hyperthyroidism
When is T3 alone typically prescribed
When patient comes in and has myxedema coma
What are some medications for hyperthyroidism
methimazole
propylthiouracil
propranolol
iodine + potassium iodine
What drugs are Thiomides
Propylthiouracil (PTU)
Methimazole
What are the MOA of PTU and methimazole
Inhibit thyroid hormone synthesis and thyroperoxidase
PTU also inhibits D1
What is the DOC for thyroid storms
PTU
Which thioamide is preferred in early pregnancy
PTU
Which thioamide is preferred in 2nd and 3rd trimester
methimazole
What are the side effects for thioamides
Teratogenic
Hepatotoxicity
BM suppression (Agranulocytosis)
What is the advantage of methimazole over PTU
Methimazole has clinical advantages and is less toxic
What is the MOA of propranolol
Non-selective beta blocker
Inhibits deiodination of T4
reduces circulating T3
What is the PK of propranolol
IV in emergent settings
What are the adverse effects of propranolol
Decrease CO
What is the MOA of iodine and KI
Inhibition of biosynthesis (iodination of tyrosine)
inhibition of secretion of T3/T4
When are the effects of iodine at their max
10 days post admin
What are the adverse effects of iodine
exacerbation of hyperthyroidism
mucosal injury
What are the indications for potassium iodide
Preoperative preparation for thyroidectomy in Graves disease to decrease gland vascularity
thyroid storm
combo treatment to improve short term control of graves
S/P admin of radioiodine in Graves disease
When is potassium iodine used most commonly
used to treat severe hyperthyroidism and to protect the thyroid gland when using radiopharmaceuticals
What is the PK of radioactive iodine
orally admin. as sodium iodide
rapidly absorbed into thyroid causing local destruction
How long does it take to inactivate the thyroid after taking radioactive iodine
6-18weeks
What are the indications for radioactive iodine
Graves
Toxic adenoma
multi nodular goiter
What are clinical presentations of hypercalcemia
Shortened QT wave
ST depression
AV blocks
What are some common causes of hypercalcemia
hyperparathyroidism
malignancy
thiazides
lithium
pancreatitis
granulomatous disease
What are some options for treating hypercalcemia
IV hydration
calcitonin
bisphosphonates
loop diuretis
glucocorticoids
denosumab
dialysis
What is the treatment for low to moderate hypercalcemia
hydration and fix underlying causes
How do you treat severe hypercalcemia
Calcitonin
Zoledronic acid
Denosumab
What is the job of calcitonin
Stimulates Ca2+ deposites in bones and decrease uptake in the kidney
What is the job of vitamin D
Increase intestinal and renal uptake of Ca2+ and stimulates release from bones to stimulate bone mineralization
What does estrogen do
Inhibits apoptosis in osteoblasts
Induces apoptosis in osteoclasts
estrogen deficiency leads to excess remodeling and bone resorption = osteoporosis
A low or intermittent levels of PTH, what effect does it have
anabolic effects of osteoblasts
If there is Hugh PTH levels, what is the cause
catabolic effects of osteoblasts
What is the MOA of bisphosphonates
Inhibits osteoclast activity which reduces bone resorption and turnover
What are medications that are bisphosphonates
Alendronate
Risendronate
Zoledronic acid
Ibandronate
What is the indication for alendronate
Osteoporosis
pagets
Osteopenia in non-ambulatory pts
What is the indication for risedronate
Osteoporosis
pagets
What is the indication for ibandronate
Osteoporosis
What is the indication for Zoledronic acid
osteoporosis
malignant hypercalcemia
bone metastesis
multiple myeloma
What are the side effects of bisphosphonates
Bone/joint/muscle pain
Nausea, heartburn, diarrhea
Upper GI irritation (Alendronate)
Headache
Atypical femur fractures
osteonecrosis of jaw
Hypcalcemia
What are contraindications for bisphosphonates
Esophageal disorders
renal insufficiency
hypocalcemia
Taking with food (30-60 min before food)
What is the MOA of calcitonin
Antagonizes effects of PTH
inhibits osteoclast activity
promotes renal secretion of Ca2+
What are the indications for calcitonin
Hypercalcemia
pagets disease
Post menopausal osteoporosis
pain from osteoporotic fx
What are adverse effects of calcitonin
Rhinitis
epistaxis
back pain
N/V
bronchospasm
hypocalcemia
anaphylaxis
What is the MOA of vitamin D
Cholecalciferol is a provitamin. The active metabolites 1,25-dihydroxyvitamin D which stimulates Ca2+ absorption from the small intestine to promote bone mineralization
What are the indications for vitamin D
Deficiency
Osteoporosis
Hypoparathyroidism
What are the adverse effects of vitamin D
Well tolerated
What are contraindications for Vitamin D
Hypercalcemia
Primary hyperparathyroidism
Sarcoidosis
What is the MOA of Calcitriol
Vit. D analog that stimulates intestinal Ca2+ absorption which decreases PTH synthesis and stimulate bone mineralization
What are the indications for Calcitriol
Renal failure
Hypoparathyroidism
rickets
hypophosphatemia
What are the adverse effects of Calcitriol
Hypercalcemia
hyperphosphatemia
N/V
What are the contraindications for calcitriol
Pancreatitis
soft tissue calcification
arrhythmias
What is the MOA of denosumab
Recombinant antibody that inhibits RANK-L to bind to RANK (antiresorptive)
What are the indications for Denosumab
Osteoporosis
Unable to tolerate/unresponsive to bisphosphonates
renal impairment
What are the side effects of denosumab
Osteonecrosis of jaw
atypical subtrochanteric fracture
bone pain
What are the contraindications of denosumab
Hypocalcemia
What is the MOA of Teriparatide (Recombinate PTH)
Anabolic affect on bone metabolism by stimulating bone formation and activating bone remodeling
treatment <2yrs / lifetime
What are the indications for teriparatide
Osteoporosis
What are the side effects of teriparatide
Generally well tolerates
hypercalcemia/hypercalciuria
orthostatic hypertension
What is the BBW for teriparatide
Osteosarcoma
What are the contraindications for teriparatide
Hypercalcemia
severe renal impairment
What is the MOA for Raloxifene
Selective estrogen receptor modifier (SERM)
acts like estrogen adonis in the bone, decreasing bone resorption and overall bone turnover = increase in bone density
What are the indications of Raloxifene
postmenopausal Osteoporosis
What are adverse effects of Raloxifene
Hot flashes
leg cramps
peripheral edema
DVT/PE
What are the contraindications for Raloxifene
History of DVT/PE
pregnancy
How do Thiazides effect calcium levels
Decrease urinary excretion Ca2+
inhibits secretion of calcium sometimes leading to hypercalcemia
How to loop diuretics effect calcium levels
Increases urinary calcium concentration
useful with hypercalcemia because it stimulates Ca2+ excretion
What therapeutic effects do the fluoride ions have on the body
Increases osteoblast activity
increase bone density
*fx risk NOT reduced
What are the toxic effects of the fluoride ion
GI effects (N/V & Diarrhea)
Renal/cardiac dysfunction
