OSTEOPOROSIS: Part 2 Flashcards
How do we manage patients at risk of fracture?
Low risk
10 year fx risk <10%
Do not treat.
Reassess in 5 years
Moderate risk
10 year fx risk 10 – 20%
Consider treatment based on
additional risk factors
and patient preference
High risk
10 year fx risk >20%
Or
Prior fragility fracture
Or
Multiple fractures
Treat with pharmacologic
therapy
if they’re moderate risks, so that 10-20% risk of fracturing in next ten years. Really it’s based on other, other risk factors they may have. So if they have really strong family history, there’s other situations that you’re concerned about. Maybe they’re getting closer to that 20%, then maybe we should be treating
With low-risk, we may re-assess with bone marrow density. It has five years, but anywhere 3-5 years is fine
How do we manage patient at risk of fracture?
What about FRAX?
Recommend treatment if:
Major osteoporotic fracture >20%
Hip fracture >3% (guidelines in U.S., in Canada we
base on major osteoporotic fracture)
Osteoporosis Medications
Antiresorptives
n Bisphosphonates
Oral:
alendronate
risedronate
Intravenous
zoledronic acid
n Monoclonal antibody against RANKL
denosumab
n Selective Estrogen Receptor Modulator
(SERM):
raloxifene
n Hormone Therapy (HT)
Anabolic agents
n Parathyroid Hormone (PTH):
teriparatide
n Sclerostin Inhibitor
romosozumab
Nowadays, most of these agents are preventative for all types including vertebral, hip and non vertebral.
raloxifene or SERM has only shown vertebral fracture reduction and it hasn’t shown non vertebral on hip fracture reduction in the studies. It could be other way the studies were done and whatever, but it’s mainly showing vertebral fracture.
Teripareatide did not show hip frac reduction but it;s just the way study was done, it’s still good anabolic agent
Studies for osteoporosis
Outcomes:
n Reducing fracture risk
§ Vertebral fractures
§ Relative risk reduction in vertebral fractures by 30 – 70%
depending on study (NNT ~ 12 - 21 in studies)
§ Hip, non-vertebral fractures
§ Relative risk reduction in hip and non-vertebral fractures
depends on agent (range 40 – 50%, NNT ~ 91 - 200 in studies)
higher bone remodeling rate, they’re more, I guess metabolic active then compare to and having trabecular bone
all studies are looking at vertebral fracture reduction as their primary outcome. Usually hip and non vertebral outcome. Non vertebral fractures are secondary outcomes. So much of the studies are powered for that primary outcome for vertebral fractures.
they have to have fracture reduction to be able to get on the market as an agent.
Osteoporosis Medications
Antiresorptives
alendronate
risedronate
etidronate* - -
zoledronic acid
denosumab
raloxifene - -
estrogen**
Anabolic
teriparatide -
romosozumab
Nowadays, most of these agents are preventative for all types including vertebral, hip and non vertebral.
raloxifene or SERM has only shown vertebral fracture reduction and it hasn’t shown non vertebral on hip fracture reduction in the studies. It could be other way the studies were done and whatever, but it’s mainly showing vertebral fracture.
Teripareatide did not show hip frac reduction but it;s just the way study was done, it’s still good anabolic agent
Antiresorptive Agents MOA
Denosumab
RANK Ligand
Inhibitor
Raloxifene
Estrogen
Reduce RANK
Ligand
Teriparatide
PTH Analog
Bisphosphonates
bind to bone
inhibit osteoclasts
RANK = Receptor activator of nuclear factor-κB
PTH = parathyroid hormone
Bisphos: bind to this hydroxy appetite in the bone. they actually get included when they bind to the part that’s already going through bone resorption, so opening. And then they get included in there. The osteoblasts come along and go over that bone. incorporated into that bone. When the next time that an osteoclast comes along, it starts to break down that bone to get it ready for bone remodeling. But it causes apoptosis,of that osteoclasts.
Denosumab: inhibiting that the rank receptors don’t get activated and therefore the osteoclasts don’t, you don’t see that normal bone resorption with the osteoclasts.
Raloxidene: reduces rank ligand so that the main action is gonna be on preventing bone resorption.
Teriparatide: PTH receptors found on both osteoclasts and osteoblasts. Intermittent administration. Exposure causes increased activity of osteoblasts. Someone who has hyperparathyroidism, e.g. you’re going to see an increase in osteoclasts activity. So terror apartheid favors when you give it in this type, it favors increasing osteoblast activity, bone formation. That’s how it’s an anabolic agent.
Considerations with Bisphosphonates
n Bind to areas of active bone remodeling
n Incorporated into bone with bone formation
n Released with bone remodeling
n Different binding affinity:
Zoledronic acid>alendronate>risedronate>etidronate
This concept is important for drug holidays!
Alendronate probably has residing time of about ten years in the bones.
Bisphosphonates
products
Oral bisphosphonate*
alendronate Fosamax®, generics
10, 70 mg tabs
70 mg/75 ml solution
Fosavance®
70 mg/2800 IU vitamin D3
70 mg/5600 IU vitamin D3
70 mg weekly
risedronate Actonel®, generics
5 mg, 35 mg or 150 mg tabs
Actonel DR® 35 mg
35 mg weekly
150 mg once a month
IV bisphosphonate
zoledronic acid Aclasta®, generic 5 mg yearly
(15 min infusion)
Oral Bisphosphonates
Adverse Effects
GI effects: abdominal pain/distension, dyspepsia
§ Diarrhea
§ Musculoskeletal: muscle, bone, joint aches/pain
Rare: Esophagitis, ulcers – alendronate, note: unclear if
risedronate has same GI issues, however patient counseling
is the same as alendronate
Diarrhea, not too common. It’s usually right in the beginning. They may get a couple of days, but usually not an issue
musculoskeletal types of pain, joint aches, muscle aches that are non-descript. Usually this is after awhile of use. It’s not right away. And if they are going to experience that it might be even a few months after regular use or usually we don’t have to take people off.
esophagitis, so irritation of the esophagus and possibly ulcers as well. More commonly with Alendronate than any of the others, alendronate has an open chain at their final and risideronate has more of a closed chain. It probably doesn’t have the same GI effects, but we recommend the same thing with them.
sitting upright for the first half-hour, these drugs are very poorly absorbed. The poor bioavailability, less than 1% of the drug is absorbed. I usually recommend up to an hour for the once weekly
Patient Counseling: Oral
Bisphosphonates
alendronate, risedronate:
n Take on empty stomach with a full glass of plain
water – best in the morning one-half hour (note:
recommend 1 hour for once weekly) before eating
or drinking
n Do not lie down for at least 30 minutes after
taking
Oral bisphosphonates have
poor bioavailability <1%
Actonel DR Formulation can be
taken with food (breakfast)
pH-sensitive
enteric coating
Bypasses
esophagus and
stomach and
delays release
until the small
intestine, where
the pH >5.5
Intended to
reduce the
binding of
risedronate with
dietary calcium
This is just information about the DR form which can be taken with food and breakfast. It has a pH sensitive enter coded coating as well as collating agent. It’s going to leave it for you don t have to memorize it or anything like that. But it’s just there to know that there is an agent that can be taken with food
IV Bisphosphonate
Zoledronic acid (ZA):
§ 15 minute infusion once a year
Adverse effects
* Acute phase reaction: flu like symptoms 1 – 3 days
after injection (fever, chills, bone pain, etc)* – can
last 3 – 4 days in 10 – 20% patients
* renal impairment
*can administer acetaminophen/ibuprofen or diphenhydramine before infusion
Monitor: calcium, phosphate, sCr/GFR prior to each dose
see a little bit more with the IV than an oral is the renal impairment that it can cause renal impairment. If we use high enough doses of the oral, it could do that as well.
But the IV you get this large dose with IV right into the system. It’s cleared. Both oral and IV are cleared by the kidneys and then the rest is taken up by the bones. So there’s about 50% that’s cleared by the kidneys and then the rest gets taken up by there.
High levels of IV in renal tubule cells can cause apoptosis of those cells, seen more with zoledronic acid
we also look at things like calcium and phosphate because just avoid like hypocalcemia
Contraindications with Bisphosphonates
n women of childbearing potential
n alendronate, ?risedronate:
§ Abnormalities of the esophagus
§ Inability to sit/stand upright for
30 minutes
Patients with renal impairment:
-Product monographs recommend
avoid if CrCl <30 ml/min
(risedronate),
CrCl <35 ml/min (alendronate,
zoledronic acid)
-Issue: most landmark trials
excluded patients with renal
impairment.
let’s say they were really kyphotic, right? They’re not gonna be able to sit upright. They can have reflux already, which agent I’m going to choose. I’m not going to choose the Alendronate. I probably would choose residronate over that, knowing that there’s probably a bit better safety if you’re looking at an oral agent,
It’s not shown to be teratogenic and there’s been lots of individuals who’ve, who’ve been of child-bearing potential, who’ve, who’ve actually been on bisphosphonates before. But it’s just, we just avoid just in case,
Drug Interactions with Bisphosphonates
Any drug that decrease the bioavailability of oral bisphosphonates:
§ calcium supplements
§ iron supplements
§ laxatives containing magnesium
§ antacid containing magnesium, aluminum or calcium
§ vitamins supplements containing minerals
§ Actonel DR – PPI’s, H2antagonist
Bisphosphonate Induced Osteonecrosis of the
Jaw (ONJ)
n What is osteonecrosis of the jaw?
n area of exposed bone in the jaw that does not heal after 8
weeks.
The theory with bisphosphonates:
n Slows bone turnover (bone turnover helps with bone healing)
n Jaw bone not able to heal properly
n More common in cancer patients on high dose IV
bisphosphonates.
n Associated with major dental issues (invasive dental
surgery, gum infections, poor dental hygiene).
n Incidence of ONJ in Canada in patients with
osteoporosis is rare
n ~1 to 69 in 100,000 patient-years
Patients with osteoporosis are greater risk of having a fracture, then getting ONJ.
n Patient education is key!
n Very small risk of ONJ
n Good oral hygiene, regular dental checkups
n Recommend holding bisphosphonate before a major dental
procedure or dental surgery, though not conclusive if it helps