Bone mineral homeostasis Flashcards
Magnesium levels effect on PTH secretion
moderate decrease in MG = inc in PTH
SEVERE decline in Mg = drop in PTH secretion
common causes of hypomagnesia
diarrhea
diuretics
alcohol abuse
chronic PPI and aminoglycoside use
PTH on intestine effect
indirect increase on calcium and phosphate absorption = via increase of vitamin D metabolite
PTH on kidney
decreased calcium excretion
increased phosphate excretion
Vit D on kidney
increased reabsorption of calcium and phosphate
net effect of PTH
increased serum calcium
decreased serum phosphate
net effect of vitamin D
increased serum calcium and phosphate
fibroblast growth factor 23
made by osteoblasts and osteoclasts = inhibits calcitrol production
dec calcium and phosphate reabsorption in kidney
Teriparatide
PTH analog
causes net increase in bone formation/mineralization
teriparatide use
osteoporosis
teriparatide kinetics
low intermit levels = anabolic effects
chronic admin = can cause primary hyperparathyroidism – catabolic effects –> osteitis fibrosa cystica
teriparatide AE
hypercalcemia - hypercalciuria
osteosarcoma
cholecalciferol
vit D analog
ergocalciferol
vit D analog
cholecalciferol/ergocalciferol use
added to calcium supplements and dairy products
regulates gene transcription via vitamin D receptor
cholecalciferol/ergocalciferol use
vit D deficiency
Rickets
osteomalacia
Vit D deficient type I
defective 1alpha hydroxylase enzyme
dec calcitriol = dec calcium, dec PO4
Vit D deficient type II
defective receptor
cholecalciferol/ergocalciferol AE
hypercalcemia, hyperphosphatemia, hypercalciuria
calcitriol
1,23-dihydroxyvitamin D3
- management of secondary hyperparathyroidism
- chronic kidney dz
- management of hypocalcemia in pt with hypoparathyroidism
(active form - doesn’t require metabolism)
doxercalciferol
1alpha-hydroxyvitamin D2
- management of secondary hyperparathyroidism in pt with chronic kidney disease
19-nor-1,25-dihydroxyvitamin D2
paricalcitol
-calcitrol analog used for management of secondary hyperparathyroidism in pt with chronic kidney disease
calcipotriene
calcipotriol
used for topical tx of psoriasis
calcitriol analog
calcitonin
peptide hormone - inhibtis bone resportion
calcitonin use
Paget disease
osteoporosis
calcitonin kinetics
salmon calcitonin = nasal spray or parenteral
calcitonin AE
rhinitis with nasal spray
alendronate
bisphosphonate
suppresses osteoclasts and inhibits bone resorption - inhibits osteoclastic activity via dec farnesyl pryophosphate synthesis via disruption of mevalonate pathway decreases osteoclast H+ ATPase
alendronate use
osteoporosis
paget’s disease
alendronate AE
esophageal irrigiation = reduced by drinking ater and remaining upright
osteonecrosis of jaw
adynamic bone
risedronate
bisphosphonate
ibandronate
bisphosphonate
pamidronate
bisphosphonate
zoledronate
bisphosphonate
ethinyl estradiol
activate estrogen receptors - changes in transcription of estrogen regulated genes
ethinyl estradiol use
prevent osteoporosis
HRT
OCP
ethinyl estradiol AE
moderate tox - breakthrough bleeding
serious tox - thromboembolism, gall bladder dz, hyperTG, migraine, HA, HTN, depression
postmenopausal women - breast CA, endometrial hyperplasia
if in combo with P450 inducer – breakthrough bleeding, dec contraceptive efficacy
raloxifene
SERM = estrogen agonist in bone, antag in breast and endometrium
raloxifene use
osteoporosis in postmenopasual women
raloxifene AE
hot flush
thromboembolism
Denosumab
RANKL inhibitor
denosumab MOA
bind RANK-L - prevents osteoclast differentiation
denosumab use
osteoporosis
denosumab AE
inc risk of infections
cinacalcet
calcimimetic
stimulates calcium sensing receptor = decreaes PTH release/suppression
cinacalcet use
hyperparathyroidism - primary and secondary
cinacalcet AE
nausea, hypocalcemia, adynamic bone
calcium preps
calcium carbonate
calcium citrate
calcium lactate
calcium prep use
hypocalcemic tetany
magnesium sulfate overdose used in eclampsia
calcium prep AE
necrosis and abscess formation
thrombophlebitis
prednisone AE
glucocorticoid
**note that the duration is longer than the half life
AE: OSTEOPOROSIS, adrenal suppression, muscle wasting, salt retention
fluoride
chronic exposure – dense but brittle bone
gallium nitrate
inhibits bone resorption
nephrotoxic
plicamycin
(mithracin)
used in cancer related hypercalcemia
plicamycin AE
thrombocytopenia
hepatic/renal insufficiency
drugs causing osteoporosis
corticosteroids heparin lithium anastrozole alcohol
drugs causing osteomalacia
phenytoin
etidronate
sevelamer
phosphate binding drug - prevents absorption in GI
tx for hyperphosphatemia
osteoporosis tx method
stop smoking, alcohol abuse, corticosteroid use
perimenopausal women == HRT
calcium Vit D supplement
bisphosphonates
SERMs
teriparatide
thiazides
decreases excretion of calcium - increased reabsorption
prevents renal stone formation
tx HTN in osteoporosis pt