IC18 Osteoporosis Flashcards
(38 cards)
What is osteoporosis? What is a possible patho?
- Porous bone, weak and brittle bones
- ↓bone mass:
o Excess bone resorption
o ↓bone formation
Patho:
- When there is ↓vit D levels → ↓Ca plasma levels → ↑Parathyroid hormone (PTH) → ↓Renal excretion of Ca + ↑resorption of bones to release Ca into blood
What are the possible causes of OP? (8)
What are the 2 major pt groups at risk of OP?
Causes:
- Age (>65y/o)
- Menopause → ↓oestrogen, weakens bone
- Alcohol
a. ↑RANKL → ↑osteoclast
b. ↑oxidative stress → ↓osteoblast - Smoking
- ↓serum Ca
- Physical inactivity
- Medication e.g. corticosteroids, cyclosporine, PPI, cancer therapy
a. Long term use of Steroids
i. Interfere with replacement and rebuilding process of bone
ii. Affect all 3 bone cell types – osteoblast, osteocytes, osteoclasts
iii. Induces ↓in osteoblast differentiation + ↑apoptosis of osteoblasts and osteocytes - Secondary to other diseases
RF:
- Postmenopausal women
- Men >65y/o
What are the S&S of OP? When will one found out that they have OP?
- Asymptomatic
- Fragility fracture (low trauma e.g. fall) → spine(height loss), hip, wrist
- Pain and disability
- If spine: Stooped posture, back pain
How to diagnose OP?
What is the T-score that shows OP?
What are the % that show you are at high risk of fractures?
Diagnosis:
- History of fragility fracture
- Do OSTA (osteoporosis self-assessment tool for asians)
- If high (>20) / medium (0-20) risk, then do DXA scan
- DXA hip/spine
a. T-score compares own BMD to young adult ref population BMD
i. T-score >-1: normal
ii. T-score -2.4 to -1: osteopenia
iii. T-score <=-2.5: osteoporosis
b. Z-score compared own BMD with expected BMD for patient’s age and sex
i. Z-score <-2: coexisting problem - Exclude secondary causes → do labs, Hx, PE
- FRAX scan
a. Start anti-osteoporotic treatment if major osteoporotic fracture risk >20% / hip fracture risk >3%
*When to treat/give meds for OP?
When to treat:
- Fragility fracture
- T-score <=-2.5: osteoporosis
- T-score -1 to -2.4: osteopenia + FRAX score shows high risk of fracture
What are the goals of treatment for OP?
Goals of treatment
- Prevent future fracture
- ↑QOL
- ↓economic burden
What is the general hierarchy in the choice of pharmacologics for OP for the 2 distinct pt groups?
What is 1st line for OP
Pharmacotherapy
- Postmenopausal women
a. (1st line) PO Alendronate / risedronate
b. IV zoledronic acid / SC Denosumab
c. Raloxifene
d. Teriparatide (ex) - Men >65y/o
- (1st line) PO Alendronate / risedronate
- IV zoledronic acid / SC Denosumab
- Teriparatide
What do you have to check before giving meds for OP?
Monitoring:
Before starting the above therapy and during (about every 3 months),
1. Check SCr, Ca &25(OH) vit D levels
a. 25(OH) vit D levels: >20-30ng/mL (normal)
b. If not enough, then give Ca and vit D supplements
BMD every 1-2 years since bone takes very slow
What is the normal 25(OH) vit D levels?
25(OH) vit D levels: >20-30ng/mL and <50-100ng/mL (normal)
What are the non-pharmacological management for OP?
Non-pharmacological management
- Ca
- Vit D
- Exercise e.g. weight bearing (30mins/day), muscle strengthening, balance (2-3x/wk) → walking, elastic band exercises, tai chi
a. ↑BMD & mass - Smoking cessation
- ↓alcohol intake
- ↓risk of falls → med review (↓meds that causes drowsiness/falls), Home environment modification/footwear/impaired vision
- Nutrition (lack of nutrition e.g. anorexia, will have weaken bones since ↓bone density / gastro-surgery)
What is the min. Ca intake?
When should you give Ca supplements?
What are the DDI of Ca?
How to manage the DDI?
What food contain Ca?
- Ca intake (>50y/o: 1000mg/day)
a. ADR: nephrolithiasis, constipation
b. Give supplementation if dietary Ca intake is <700mg/day
c. DDI:
i. ↓Ca absorption: PPI, fibre
ii. ↓ following drug’s absorption (Gaviscon have Ca): Fe, tetracyclines, fluoroquinolones, bisphosphonates, thyroid
d. Management: space Ca & bisphosphonates 2 hrs apart → e.g. bisphosphonate taken 1/2hr before breakfast, then eat breakfast, then take Ca
e. Food: milk, yoghurt orange juice
What is the amt of Vit D that should be given if it is below normal range?
What are the DDI with vit D?
Normal range: >20-30ng/mL
- Vit D intake (50-70y/o: 600IU/day; >70y/o: 800IU/day)
a. Give 800IU/day cholecalciferol when vit D insufficient
b. DDI: anticonvulsants (PHY< CBZ, VA), rifampicin, cholestyramine, orlistat (fats), aluminum-containing products
What is the dose and dosing interval of all your bisphosphonate?
What is the total duration?
Admin.:
- For PO (cheapest):
Treatment Alendronate: 70mg once weekly
Prevention Alendronate: 35mg once weekly
Risedronate: 35mg once weekly
Risedronate: 150mg once monthly - For IV: 5mg once yearly as 30min infusion, if Ca/vit D def take Ca+ vit D before infusion
Duration:
- 5years for PO
-
3years for IV
If high fracture risk (T-score<-3), then 10years PO, 6years IV
What is the MOA and place in therapy of bisphosphonates?
- slow bone loss by ↑osteoclast cell death
Place in therapy:
- PO are 1st line (mild-sev)
→ convenient, cheap, effective, acceptable ADR
What are the ADRs of bisphosphonates?
Common:
PO:
1) Nausea
2) abdominal pain
3) Diarrhea
4) Heartburn like sx
5) Sev bone, joint, muscle pain
IV:
6) Flu-like sx
7) Hypocalcemia
8) Fever, malaise, headache, musculoskeletal aches
9) Ocular effects
Rare:
9) Atypical femur fracture (prolong use)
- Stop bisphosphonates
10) Osteonecrosis of jaw/ear
RF: tooth extraction, cancer, radiotherapy, poor oral hygiene, other drugs e.g. steroids, denosumab
Advise: smoking cessation, good oral hygiene, avoid dental procedures
What are some counselling points when taking bisphosphonates?
For PO:
1) take at least 30mins before breakfast in the morning
2) A glass of plain water
3) Sit up and do NOT lie down for 30mins (to prevent acid reflux & irritation)
*What are the CI of bisphosphonates? (5)
CI:
1) Hypocalcemia
2) esophagus abnormalities / reflux for PO (can delay emptying)
3) Sev renal impairment
CrCL: <35mL/min (IV)
CrCL: <30mL/min (PO)
Since kidneys are impt in regulating blood Ca levels
4) Preg & Lact
5) inability to stand / sit upright >30mins
6) aspiration risk (inability to swallow well)
Precaution:
- Active upper GIT disease
- RF for developing osteonecrosis
What is the patho of Denosumab?
How to administer it?
SC Denosumab
- human mab against RANKL (RANK Ligand)
- prevents development of osteoclasts
- similar efficacy as bisphosphonates
Admin.:
- SC once q6months
- co-administer 1000mg Ca + >400IU vit D daily (due to intense ↓osteoclast resorption, thus sign. ↓plasma [Ca])
What are the ADRs of denosumab?
What are the special precautions & CI?
1) Muscle, back, bone, joint pain
2) N&V
3) C&D
4) slight tiredness
5) Hypocalcemia
6) ↑cholesterol
Rare (the mabs):
6) Osteonecrosis of jaw
7) Atypical femur fracture
Do NOT discontinue as may ↑risk of spinal column fractures
Special Precaution:
- Sev renal impairment CrCL<10mL/min
CI:
1) Hypocalcemia
2) Preg
Which drug causes ONJ & atypical femoral fracture?
bisphosphonates, denosumab, romosozumab,
Which drug can be used when CrCL<30mL/min?
SC denosumab & (SC Romosozumab but special precaution)
PO Bisphosphonates <30mL/min
IV Bisphosphonates <35mL/min
SC Denosumab <15mL/min (special precaution)
Raloxifene <30mL/min
SC Romosozumab <30mL/min (special precaution)
SC Teriparatide <30mL/min
Who is oestrogen mainly indicated for?
Indicated only for:
- bone health in younger women
- women w menopausal sx that needs treatment
- premenopausal w ↓BMD/ postmenopausal
What is the MOA of raloxifene?
- selective estrogen receptor modulator (mix agonist & antagonist)
- (agonist aspect) mimics effects of estrogen on bone density
- (antagonism aspect) ↓risk of breast cancer, CV ADR
What are the ADRs & CI of raloxifene?
ADR:
1) VTE & stroke
CI:
- Sev renal impairment CrCL<30mL/min
