Osteoporosis

Question 1

Definition of OP

Answer 1

Low bone mass, microarchitectural deterioration leading to fragility & fracture (fx)

Question 2

DXA scan

Answer 2

-Dual energy x-ray absorptiometry
-Preferred tool
Central sites (hip, femoral neck, & lumbar spine) preferred
-More likely to show response to treatment
-Consistency between machine and operator ideal

Question 3

Tscore

Answer 3

• Relative bone mineral density (BMD) measure
• Expressed in standard deviations (SD) from BMD of a young adult mean (of the same sex)
• Normal: within 1 SD
• Osteopenia: -2.5 < SD < -1
• Osteoporosis: SD ≤ -2.5

Question 4

Drugs that risk factors for OP

Answer 4

• Glucocorticoids
• Lithium
• excessive thyroid replace
• heparin (long term)
• Chemo
• GRH drugs
• phenytoin
• tamoxifen pre-menopausal
• progesterone

Question 5

Calcium & Vitamin D

Answer 5

• essential part of all prevention & treatment plans

- Vitamin D: Facilitates active transport of calcium in small intestine

Question 6

Vitamin K

Answer 6

-Vitamin K involved in osteocalcin, involved in bone formation
-Deficiency can contribute to bone loss
-Data conflicting and insufficient to recommend
If supplementing, be careful of interaction with warfarin

Question 7

Isoflavones

Answer 7

• Dietary soy products

- Data is conflicting

Question 8

Bisphosphonates

Answer 8

-MOA: Mimic pyrophosphate (endogenous bone resporption inhibitor)
—Antiresorptive activity leads to decreased osteoclast maturation, number, recruitment, bone adhesion, and life span
-Effect
↑ BMD
↓ spine fractures
↓ hip fractures—very important benefit
-Avoid in renal impairment: CrCl approx. < 35 ml/min
-Very long half-life (possibly > 10 yr when incorporated in bone)
-Osteonecrosis of the jaw

Question 9

Bisphosphonate drugs

Answer 9

• Alendronate (Fosamax®)
• Risedronate (Actonel)
• Ibandronate (Boniva)
• Zoledronic (Reclast)

Question 10

Denosumab

Answer 10

• Treatment in women & men
• Men receiving androgen-deprivation tx for nonmetastatic prostate ca
• Women receiving adjuvant aromatase inhibitor for breast ca
• Monoclonal antibody
• Need to correct hypocalcemia before initiation

Question 11

Raloxifene & Bazedoxifene

Answer 11

-MOA: Selective estrogen receptor modulator (SERM)
Binds to estrogen receptors activates some paths (bone) & blocks others (breasts,uterus,etc.)
-Indications: Post-menopausal OP

Question 12

Calcitonin

Answer 12

-MOA: Synthetic polypeptide hormone (salmon)
Receptors on osteoblasts & osteoclasts
Inhibits bone resorption
Possible ↓ in osteoclast # & ↑ in osteoblast activity

Question 13

Estrogen

Answer 13

↓ osteoclast activity
↓ bone resorption
↑ calcium absorption from GI
↓ calcium renal excretion
Inhibits PTH peripheral action

Question 14

Testosterone

Answer 14

• Not FDA approved for men
• Guidelines recommend testosterone alone for men with testosterone concentrations < 200 ng/dL if low fx risk and in cobo with other medication if fx risk high

Question 15

Teriparatide (Forteo)

Answer 15

-MOA: Recombinant human parathyroid hormone (PTH) (1-34)
Once daily PTH stimulates osteoblasts (more than osteoclasts)  new bone formation
vs. continuous endogenous PTH causing bone resorption
-Black box warning
↑d osteosarcoma incidence in rats
-Expensive

Question 16

Romosozumab

Answer 16

• FDA indicated for postmenopausal women at high risk for facture
• Humanized monoclonal antibody
• Adverse effect:
• –HA, arthralgia, hypercalcemia, rare osteonecrosis
• -Black box warning: MI, CVA, CV death

Question 17

Combo tx

Answer 17

• Teriparatide + Bisphosphonate
• Teriparatide + raloxifene
• Bisphosphonate + estrogen or raloxifene
• -Estrogen + calcitonin