Osteoporosis Flashcards
what is osteoporosis?
changes in bone mass with age, bone mass increase until we are 30, goes stagnant, and then decreases
disease related osteoporosis
hypogonadism, hyperparathyroidsim, hypertyroidism
drug induced osteoporosis
gluccocorticoids (3rd leading cause), thyroid replacements, GnRH agonists/antagonists, aromatase inhibitors (breast cancer)
how fast can osteoporosis occur
fast, can deteriorate in 3-6 years
bone remodeling cycle
resting surface osteoclast-mediated resorption recruitment of osteoblasts secretion of new matrix calcification of said matrix
creating an osteoclast?
rankl binds to rank on an osteoclast precursor developing it into a mature osteoclast, this also secretes factors that allow osteoblast precursors to mature into osteoblasts
remember the drugs
abcder t
antiresorptive agents
bisphosphonates (alendronate zoledronate ibandronate) calcitonin denosumab estrogen raloxifen
bisphosphonates
alendronate(oral daily)
zoledronate(iv yearly)
ibandronate(oral daily, monthly or iv 3 mo.)
mechanism of action for bisphosphonates
high affinity for bone, ca chelator, incorporates and stabilizes structure. Inhibits bone resorption by decreasing osteoclast function and increasing their apoptosis
uses and admin of bisphophonates
osteoporosis due to aging, PMW, steroids
oral admin, less than 10 percent absorbed; water only; upright position to prevent heartburn, and esophageal irritation
high doses of bisphosphonates puts you at risk for ______.
osteonecrosis of the jaw
Toxicity of zoledronate
renal toxicity
Denosumab
binds to RANKL (receptor for activating NFKB ligand) thus decreasing activation of rank and thus decreasing osteoclast formation/activation
Admin and adverse effects of denosumab
admin: sc injection every 6 mo
adverse effects: increase infection risk?
calcitonin
thyroid gland hypocalcemic hormone
decrease bone resorption by decreasing osteoclast surface area
vitamin d and calcium supplements
increase calcium absorption in small intestine (increase bone mineralization)
at large doses however it act in bone resorption
uses of calcitonin
PMW, steroids, low efficacy(fracture prevention?)
estrogen
decrease bone reabsorption by decreasing rank L and cytokines thus decreasing osteoclasts proliferation and activation, and decreases osteroBLAST apoptosis
Long term risks of estrogen
In pmw: breast cancer, thromboembolism, stroke, cv risk
LIMITED USE: NON RESPONDERS TO OTHER TX
Raloxifen
selective estrogen receptor modulator
estrogen receptor agonist in breast endometrium
decreases osteoclast formation and activation thus decreasing resorption and fractures in PMW
Uses of raloxifen
osteoporosis in PMW w/ breast cancer or family history
administration of ralozifen
oral daily
adverse effects of raloxifen
risk of venous thrombosis, pulmonary embolism
bone forming agents
teriparatide
teriparatide
active peptide of parathyroid hormone
hyper parathyroidism= bone resorption
low, intermittent PTH (teriparatide) = bone growth
increases osteoblast number and activation
uses of teriparatide
severe osteoporosis, high fracture risk
admin of teriparatide:
daily s.c, injection for 2 years
adverse effects of teriparatide:
may increase risk of osteosarcoma (rats?)
