Osteoporosis Flashcards
How is osteoporosis defined clinically?
Low bone mass defined by distance from standard deviation on DEXA score
Differentiate osteoblasts from osteoclasts.
Osteoblasts: build bone
Osteoclasts: break down bone
What is the biggest risk factor for osteoporosis?
Estrogen deficiency, particularly after menopause
T/F: Women over the age of 65 lose bone mass at a faster rate than males of the same age.
False: but women have lower bone mass to start with, so they are at greater risk
List 8 risk factors for developing osteoporosis.
Advancing age, poor calcium and vitamin D intake, glucocorticoid therapy, low body weight, smoking, excessive alcohol, sedentary lifestyle, overuse of aluminum containing antacids.
How much of a steroid dose is needed to decrease bone mass?
Daily dose of 5mg of prednisone (or equivalent) for 3 or more months
List some non-pharmacologic interventions indicated for osteoporosis patients.
Smoke and alcohol cessation, fall prevention, regular weight bearing exercise, adequate intake of calcium and vitamin D
Describe the three salt forms of calcium in terms of the elemental calcium each form delivers.
Ca carbonate: delivers 40% elemental calcium
Ca citrate: delivers 24% elemental calcium
Ca gluconate: minimal elemental calcium
What patients should avoid taking calcium carbonate and why?
Patients taking PPIs or H2RAs –> calcium carbonate requires acid to be absorbed
What are the AEs of calcium supplementation?
GI effects - constipation, nausea, gas, etc.
Hypercalcemia - especially when combined with a thiazide
Hypophosphatemia - calcium binds phosphate
Kidney stones (hypercalciuria)
Chelator (Ca carbonate) - binds quinolones, tetracyclines, bisphosphonates
Describe the mechanism of action of vitamin D supplementation as it relates to osteoporosis.
Vitamin D is required for the intestinal absorption of calcium
List and describe the three forms by which vitamin D is available.
Ergocalciferol (D2): requires 1-alpha-hydroxylation in kidneys to convert to active form
Cholecalciferol (D3): also requires 1-alpha-hydroxylation and is naturally formed in the skin via sunlight
Calcitriol (1,25(OH)D3): does not require 1-alpha-hydroxylation –> best for CKD patients
T/F: Vitamin D is a fat soluble vitamin that is absorbed in the stomach.
False: Fat soluble but it is absorbed in the intestines
T/F: All vitamin D supplement forms are available OTC.
False: higher strength vitamin D is available by prescription only and may be available by injection
What is the mainstay of osteoporosis therapy?
Bisphosphonates
What are the indications (including off-label uses) for bisphosphonate use?
Osteoporosis, Paget’s Disease, bone metastases
Off-label: decreased bone mineral density from IBD, hypercalcemia of malignancy
Describe the mechanism of action of bisphosphonates.
Incorporated into bone in areas of active bone remodeling. There they decrease activity of osteoclasts allowing osteoblast activity to prevail
Describe the duration of activity of bisphosphonates.
Long duration because they are incorporated in the bone matrix.
Name and describe the first bisphosphonate.
Alendronate: first and least expensive, many dosing options (qd tablet, qw tablet, liquid)
Describe the 30 minute rule of bisphosphonates and describe how Ibandronate is different.
Patients must take most bisphosphonates 30 minutes before eating and remain standing for 30 minutes after to allow the drug to travel easily down the esophagus and into the stomach –> risk for esophageal ulcers. Ibandronate requires 60 minutes standing.
T/F: Ibandronate is only available as a PO tablet.
False: It is also available IV
What is unique about the administration of Risedronate?
Must be taken with water immediately AFTER breakfast
Describe the administration of Zoledronic Acid.
It is administered IV once per year.
List the disadvantages of Zoledronic Acid.
Expensive, may cause nephrotoxicity and infusion reactions.
