Osteoporosis Flashcards
what maintains serum calcium?
Parathyroid hormone
what organ does PTH act on to reabsorb calcium from the tubular filtrate?
kidney
PTH stimulates kidney to convert 25-OH-VitD to what?
1,25-(oh)2-VitD (calcitriol)
what is the endogenous (skin) form of vitamin D?
cholecalciferol (Vit D3)
What is the exogenous (diet) form of Vit D?
ergocalciferol (Vit D2)
this comes from the thyroid gland and is released in response to really high serum calcium levels.
Calcitonin
1 to 2.5 standard deviations below bone mass of a normal young adult
Osteopenia
It is 2.5 or more standard deviations below the bone mass of a normal young
Osteoporosis
What form of osteoporosis occurs in older people (usually >70), postmenopausal women
primary osteoporosis.
Type of osteoporosis that occurs in people with hyperthyroidism, steroid use, chronic kidney disease, smoking, excessive ETOH
secondary osteoporosis
does excess or too little protein in the diet lead to osteoporosis.
excess
what are some modifiable risk factors for osteoporosis
Inadequate calcium and Vit D Alochol use sedentary carbonated drinks smoking anorexia
what drugs used long term can lead to osteoporosis?
heparin lithium anticonvulsants thiazolidinediones aluminum cytotoxic drugs immunosuppressnats TPN GnRH agonists progesterone tamoxifen
What are Gonadotropin-releasing hormone agonist used for?
Polycystic Ovarian Syndrome
helps patients have normal cycles
who should be tested for osteoporosis?
All women >65 ( >60 w/ risk factors)
men >70 (>50 w/ risk factors)
Only calciums in IV preparation
Calcium gluconate (replacement) Calcium chloride (code)
What calcium are available in PO form?
calcium gluconate
calcium carbonate (tums)
calcium lactate
calcium citrate
what type of calcium is also available in liquid form?
Calcium citrate
Indications for calcium
Hypocalcemia
calcium deficiency
osteoporosis or osteopenia
ADRs with calcium
GI problems
constipation
bradycardia
arrhythmias
what should be monitored anytime calcium is given IV?
monitor serum calcium levels every 6 hours
Inactive form of vit D (required liver and kidneys to convert)
ergocalciferol
what is the active form of Vit D?
calcitriol
MOA of Vit D?
acts on the gut to absorb calcium from the diet
Routes available for Vit D?
Oral
IV
UV reaction in skin
Indications for Vit D replacement
Hypocalcemia
Vit D deficiency
Postmenopausal osteoporosis
renal failure
Expensive drug, recombinant paraythroid hormone that stimulates osteoblastic activity
Teriparatide
When is teriparatide only used?
Hx of osteoporotic fractures
multiple risk factors and failed/ intolerant to other therapies
ROA of teriparatide
20 mcg SubQ qday
C/I with teriparatide
Paget’s dz
increased alkaline phosphatase
h/o radiation treatment
ADRs w/ teriparatide
dizziness, leg cramps
Transient increase in serum calcium
black box warning w/ teriparatide
osteosarcoma
what are Structural analogs of pyrophosphate
bisphosphonates
MOA of bisphosphonates?
MOA: works by inhibiting bone resorption via:
Inhibits osteoclastic proton pump necessary for dissolution of hydroxyapatite
Decreased osteoclastic formation/activation
Increased osteoclastic apoptosis
bisphosphonates that are avaliable PO
alendronate (once a week)
risedronate (once a week)
ibadronate (once a month)
What bisphosphonates are given IV?
zoledronic acid (hypercalcemia of malignancy)
PO bisphosphonates should be administered how?
With a full glass of water
30 minutes before a meal
remain upright for 30 minutes
C/I w/ bisphosphonates
renal impairment/ hypocalciemia
CrCl < 30-35 ml/min
what is a potential problem w/ the PO form of bisphosphonates
esophageal erosion
ADRs w/ IV form of bisphosphonates
Acute phase reactions (N/V, HA, myalgias, flue like symptoms)
works to increase mineral stores in bone, decreases activity of osteoclasts (and number) and acts in kidney. Found in salmon. increases spine BMD, bone architecture
calcitonin
ROA of calcitonin
intranasal
SubQ
what is calcitonin used for?
Hypercalcemia
Paget’s dz of the bone
bone pain in metastatic dz
bone pain in osteoporosis
ADRs of calcitonin
tingling in hands
N/V
flushing
Advnatages of calcitonin nasal spray
don’t have to remain upright
don’t have to avoid eating
disadvantages of calcitonin nasal spray
Is not as good at rebuilding bone
Must remember which nare medication was placed previous day.
Tolerance with continued use
Must keep refrigerated
Acts like an estrogen in the bone, but estrogen antagonists in the breast and uterus. Decrease serum LDL and decreases vertebral fractures
Raloxifene
When to use raloxifene
1st line if patient postmenopausal and contraindication to bisphosphonates
ADRs with raloxifene
Chest pain and peripheral edema
3x risk for thromboembolism and PE
hot flashes, weight gain
What is a 4th line treatment for osteoporosis
estrogen
disadvantages of estrogen
increases risk of breast cancer
need to give w/ progesterone if intact uterus
increased risk of thromboembolitic events
monoclonal antibody that slows bone breakdown and remodeling, is costly
Denosumab
who is Denosumab approved for?
Postmenopausal women with osteoporosis and high risk of fracture
Patients with osteoporosis for whom other osteoporosis treatments have failed.
Patients who cannot tolerate other osteoporosis treatments
ADRs of denosumab
decrease Ca levels back and extremity pain muscle and bone pain high cholesterol levels bladder infections
