osteoporosis Flashcards
Osteoporosis: Occurs when rate of bone _______ exceeds rate of bone _______
resorption
formation
what is the normal bone resorption process?
osteoclasts activation stimulated by RANKL
what is the activation of bone resorption in the pathologic process?
osteoclasts activation stimulated by PTH
metastatic disease
what is the process of bone formation? what are the 4 natural substances that promote this?
Inhibition of osteoclast, stimulation of osteoblasts Osteoprotegerin (OPG) calcitonin estrogen IL-10 inhibit osteoclast
what two main groups of natural substances regulate bone metabolism? what does is group include?
Hormones:
PTH, calcitonin, estrogen, androgens
Steroids:
Vitamin D, glucocorticoids
what do osteocytes do?
- formed after osteoblast activity
- release chemicals that say we need more osteroblast or clast activity (regulators)
what is OPG? (where does it come from and what does it do?)
released by osteocyte, it inhibits bone resorption by binding RANKL (holding it hostage so it cant activate osteoclasts)
what does RANKL do?
binds to RANK on osteoclast - activates the osteoclast
how does PTH exposure differ with release low intermittent vs high chronic?
low intermittent- bone formation (anabolic axn)
high chronic- bone resorption (breakdown) (catabolic axn)
how does PTH increase bone turnover?
PTH stimulate osteoblast to secrete IL-1, IL-6 and RANKL to activate osteoclast activity
RANKL binds to RANK proteins triggering the osteoclasts
Result is bone turnover and remodeling
PTH regulates what two substances? using what 3 organs?
Regulates calcium & phosphate using bone, kidney, and intestines
what does PTH do in the kidney?
Stimulates 1- α hydroxylase to convert calcidiol to calcitriol (to give active vitamin D - allows us to absorb Ca+ from intestine)
-tell kidney to keep Ca+ (DistalT) but get rid of phosphate (ProximalT)
what does PTH do in the intestine?
Indirectly increases intestinal calcium absorption by stimulation of 1,25 dihydroxyvitamin D production
Vitamin D: Increases serum ___and contributes to bone ______
calcium, mineralization
why is it so important to maintain Ca+ and phosphate balance? - (what if they get too high?)
need to maintain so they dont precipitate and accumulate in places like the lungs
what is the net effect of calcitonin?
Increase serum calcium -> calcitonin secretion -> inhibition of osteoclast -> decreased serum calcium
what is a hypocalcemic hormone that OPPOSES the effect of PTH?
calcitonin
estrogen’s effect on osteocyte, blasts and clasts
- decrease osteocyte and osteoblasts apoptosis
- increase osteoclast apoptosis
what is estrogen good for in regards to bone health? why is this important?
Estrogen is better at preventing bone loss than building bone.
dont give post- menopausal women estrogen to increase bone density unless last resort (other agents are better)
glucocorticoid’s effect on bones?
Antagonize vitamin D effect (decreasing intestinal calcium transport)
Blocks bone formation by inhibiting osteoblast activity
=overall : block bone formation
prolonged exposure to steroids can cause what effects in adults? children?
prolonged exposure to steroids can cause osteoporosis in adults and stunts skeletal development in children
what Can be useful at reversing hypercalcemia associated with lymphomas?
glucocorticoids
7 agents used to affect bone mineralization
Bisphosphonates Human parathyroid hormone related peptide analogs Monoclonal Antibody Sclerostin Inhibitor Conjugated Estrogens/SERMS Calcitonin Calcium Vitamin D
Drug of choice (first line) for treatment of osteoporosis
bisphosphonates
what are the bisphosphonate drugs?
*Alendronate (Fosamax)
*Risedronate (Actonel, Atelvia)
Ibandronate (Boniva)
Zolendronic acid (Reclast)- IV formulation (once a year infusion)
only bisphosphonate that is not first line b/c no help for hip/nonvertebral fractures
ibandronate (boniva)
which bisphosphonate is IV formulation - (once a year infusion)
zolendronic acid
bisphosphonate MOA
bind Ca+ - taken into bone in high concentrations
they are taken up by osteoclast (and destroy the proteins that make their fringe border so they can’t chew up the bone)
= osteoclast apoptosis = decr rate of resorption
what is important to remember about the abs. of oral bisphosphonates?
When given orally little is absorbed – less than 1%
must take on empty stomach for max absorption
any metabolism for bisphosphonates?
no!
1/2 life of bisphosphonates
After binding to bone, clearance is hours up to 10 years (what does get abs. - that 1%- stays around for a while)
1 ADR for bisphosphonates?
GI irritation
rare ADRs of bisphosphonates?
Osteonecrosis of jaw. AVN=avascular necrosis of jaw. (due to lack of blood flow to bone.)
-dental procedures in patients with cancer after prolonged chemo therapy
which type of administration of bisphosphonates has higher risk for AVN - high dose IV or oral?
High dose IV administration
contraindications for bisphosphonates? (3)
Renal dysfunction
Esophageal motility disorders (tablet sits in throat and erodes it)
PUD
instructions for taking oral bisphosphonate
Taken alone on empty stomach in morning with 8 oz of water (Water reduces risk of tablet getting stuck in esophagus)
Remaining upright for 30 minutes to minimize risk of reflux (ibandronate is 60min)
which is the one bisphosphonate that actually SHOULD be taken with food?
Risedronate sodium delayed release (Atelvia) must be taken with food
what type of fractures are the fractures with greatest morbidity & mortality?
Vertebral and hip
why are bisphosphonates so good for a first line for osteoporosis?
They increase bone density and prevent vertebral & hip fx (they hit BOTH)
before starting bisphosphonates, what should pts be evaluated for?
to detect potentially treatable causes for osteoporosis - is there anything else causing the osteo that we can stop?
Labs: Calcium (hypocalcemia); 25-hydroxyvitamin D (Vit D Deficiency); Creatinine (Renal impairment)
what is a “Tscore” ?
measurement of bone density - measured in std deviations (lower than -2.5 is definition of osteoporosis)
for what pts can we discontinue bisphosphonates and reevaluate in 2-3 years? why can we do this?
if they were on alendronate or risendronate for 5 years
or Z. acid for 3 years
AND have stable BMD, no previous fractures and low risk for fracture.
*it stays in body for 10 years.
what is the reevaluation rules for if a pt has a low Tscore?
this means they are at high risk for future fractures
Taking alendronate/risedronate-continue 10 years
Taking zoledronic acid – continue 6 years
what are the human PTH -related peptide analogs (recombinant PTH)? what is the MOA?
Teriparatide (Forteo) & Abaloparatide (tymlos)
MOA: PTH in pulse form = osteoblast increase
The only anabolic therapy for bone; it increases bone mineral density, bone mass & strength
(other meds prevent resorption)
recombinant PTH analogs- “paratides”
3 contraindications for teriparatide & abaloparatide
- hx of bone metastases
- if at risk for osteosarcoma
- hypercalcemia
whose at risk for osteosarcoma?
(Paget’s disease, unexplained increase in alkaline phosphatase, pediatric patient, h/o radiation therapy to the bones)
teriparatide + abaloparatide- Only give for __ years (during a patients life time) then switch to _________ for further treatment. why?
2 years
Bisphosphonates for further treatment b/c of potential risk of bone cancer
Human parathyroid hormone related peptide analogs (“paratides” ) are used for what 2 groups of pts?
- women at high risk of fracture, including those with very low BMD and a previous vertebral fracture
- hypogonadal osteoporosis in men w/ high risk of fracture
“paratides” and bisphosphonated together?
no! it decreased BMD
what should you remind pts when they are prescribed the “paratides” ?
take first dose lying down b/c of orthostatic hypotension
1xday injectable
Denosumab (Prolia/Xgeva) MOA
binds to RANKL, prevents differentiation of osteoclast, leads to inhibition of osteoclast fxn and survival –> osteoclast apoptosis
denosumab ( prolia or xgeva) what are they used for?
Prolia – osteoporosis/steroid induced osteoporosis
Xgeva – bone metastases from solid tumors, multiple myeloma
(same drug, just different dosing)
what is our one sclerostin inhibitor drug?
Romosozumab-aqqg (Evenity)
MOA of romosozumab (evenity)
inhibits axn of sclerostin . stimulating osteoblast activity while slightly decreasing osteoclast activity
(increases bone formation)
sclerostin inhibitor (romosozumab-aqqg) is indicated for what use?
treatment of osteoporosis in postmenopausal women at high risk for fracture
what defines “high risk of fracture”
Defined as a history of osteoporotic fracture
OR multiple risk factors for fracture
OR patients who have failed or are intolerant to other available osteoporosis therapy
how long can you use the sclerostin inhibitor for? if osteoprosis remains after this time period, what can you switch to?
12 monthly doses (doesnt work anymore after a year)
* continued therapy with an anti-resorptive agent should be considered
what is the one SERM we may use for osteoporosis?
Raloxifene (Evista)
MOA of Raloxifene (Evista) ?
estrogen agonist used to reduce resorption of bone and decrease in overall bone turnover
what is raloxifene (evista) good for?
Treatment and prevention of osteoporosis in postmenopausal women
Reduces risk of vertebral fractures by 30-50% (not for hip fractures)
major ADR to look out for raloxifene (evista) ?
clots (First 4 months) (DVT)
MOA of conjugated estrogen/bazedoxifene
Estrogen is agonist, Bazedoxifine is agonist on bone and antagonist in uterine tissue to prevent endometrial hyperplasia
(SERM)
what does calcitonin (miacalcin) do to PTH? from where do they get this hormone ?
Antagonizes effects of PTH and inhibits bone resorption (increases bone density but DOES NOT prevent fractures)
-salmon derived hormone
when would you use calcitonin for osteoporosis?
doesnt work very well - only really good for BONE PAIN
3rd line if you go to it at all
why is Calcium recommended for all osteoporosis pts to take? (2 reasons)
- maintain normal calcium concentrations
- to prevent hypocalcemia associated with other drug treatments
what is the dosing for calcium?
1000 mg daily (19-50 years women & 51-70 years men)
1200 mg daily (51-70 years women & >70 men & women)
Avoid doses higher than 2000 mg/day
what does total daily calcium include?
Total daily calcium includes diet and supplements - obtaining it naturally better than taking tablet
why is Vit D recommended for all osteoporosis pts?
Maximizes absorption of calcium by intestine
minimal dosing of vitamin D: men 70+ and post-menopausal women vs premenopausal women and men <70
Men over 70 and postmenopausal women is 800 IU/day
Premenopausal women and men < 70 is 600 IU/day
*txt of osteoporosis: no prior fracture/moderate risk: 1st line (4)
Bisphosphonates: Alendronate, Risedronate, Zoledronic acid
Denosumab
*txt of osteoporosis: no prior fracture/moderate risk: alternative options (3)
Bisphosphonate: ibandronate (for vert. fracture risk)
SERM: Raloxefine, Conjugated estrogen/Bazedoxifene (Duavee)
*lifestyle measures for txt of osteoporosis (5)
adequate calcium and vitamin D exercise smoking cessation counseling on fall prevention avoidance of heavy alcohol use
*txt of osteoporosis: Hx fracture/high risk: 1st line (3)
Denosumab
Teriparatide, abaloparatide
Zoledronic acid (IV)
*txt of osteoporosis: Hx fracture/high risk: 1st line (2)
Bisphosphonates: Alendronate or Risedronate
special case of osteoporosis: men. txt? what if testosteron is low?
Avoid risk factors, treat with bisphosphonates.
If serum testosterone level is low can give testosterone injections
special cases of osteoporosis: men - severe. what drugs can you use?
Denosumab, teriparatide
special case: glucocorticoid-induced osteoporosis. txt?
higher doses Ca+ and Vit D
bisphosphonates
special case: glucocorticoid-induced osteoporosis - severe. txt?
Severe cases: teriparatide
special case: premenopausal women. what 3 things should be recommended as far as prevention?
Calcium, vitamin D, weight bearing exercise
special case: premenopausal women- hypogonadism vs steroid-induced txt
Hypogonadism – estrogen replacement
Steroid induced – alendronate, risidronate; severe – teriparatide
what 3 drugs to avoid for premenopausal women with osteoporosis
NO SERM’s, calcitonin, denosumab
what is paget’s disease?
Resorb bone and then lay down, new poorly organized bone.
Results in overgrowth of bone at single or multiple sites - spikes and bony nodules- painful for pt
goal of txt for paget
Goal of treatment is to reduce bone pain & reduce rate of bone remodeling
txt options for bisphosphonates (2 main options)
Bisphosphonates 1st line agents - at higher dosing than for osteop.
Zoledronic acid
Alendronate
Risedronate
Calcitonin
Reserved for bone pain or when bisphosphonates not tolerated
