Chapter 79 Drugs Affecting Ca++ and Bone Mineralization Flashcards
What is the primary purpose of Ca++?
Helps with skeletal, neuromusuclar and cardiac fx
Where is Ca++ stored?
98% in in bones
Total serum Ca++ = 10mg/dL
Blood takes precedence over bone
What increases Ca++ resorption from the bone?
PTH and Vit D
What does PTH + Vit D do for calcium?
PTH = Increase calcium resorption from the bone, kidneys, and Vit D activation (further Ca++ absorption from the intestines)
Vit D = Increases calcium reposition from bone, decrease calcium excretion from kidneys, and increases absorption from GI
All together now = holds onto calcium for the blood!
What does calcitonin do for calcium?
Hormone from thyroid that helps with excretion of Ca++ if values are too high via kidney excretion (pee) and stops resorption from bone (keeps Ca++ in the bone)
You put the tone in the bone!
DOES NOT INFLUENCE ABSORPTION RATHER FOCUSES ON RIDDING CALCIUM WHEN SERUM LVLS ARE HIGH
What is sarcoidosis?
a chronic inflammatory disease that causes the formation of small, non-cancerous clumps of cells called granulomas in various organs of the body which can be caused by hypercalcemia
What are ways to lower Ca++?
Drugs that…
Promote excretion
Decrease mobilization
Decrease intestinal absorption
Formation of complexes with free calcium in the blood
How resorption of the bone works? (just informational)
Osteoclasts: Specialized cells called osteoclasts are responsible for bone resorption.
Dissolving bone: Osteoclasts dissolve bone minerals and break down the bone matrix (collagen and other proteins).
Releasing minerals: This process releases calcium and phosphate into the bloodstream.
What is Cinacalcet when looking at a pt w/ hypercalcemia?
it is a calcium reducing agent that helps suppress PTH secretion; used with hypercalcemia associated with hyperparathyroidism
What is rickets?
Seen in children who have lower dietary vitamin D intake (via sun or food) resulting in defective bone growth and deformities
Osteomalacia is what?
Adult counterpart of rickets d/t poor vitamin D intake in adulthood resulting in kyphosis, bowlegs, fractures.
Paget’s disease is what?
Increase bone resorption and replacement of resorbed bone with abnormal bone resulting in pain, deformity, and fractures
Hypoparathyroid is what?
Lack of PTH (removal) resulting in hypocalcemia
Hyperparathyroid is what?
Too much PTH secretion (adenoma) resulting in increase in calcium
THIS IS WHEN YOU WOULD PRESCRIBE CINACALCET to lower calcium
What do calcium salts do? A/e? Drug interactions?
Given PO used for mild to moderate hypocalcemia.
Given IV (calcium gluconate) for SEVERE hypocalcemia
A/e - hypercalcemia
DI - loop diuretics + calcium salts = hypocalcemia (increasing calcium excretion)
thiazide diuretics + calcium salts = hypercalcemia
(do not propagate calcium excretion, thus overload)
What is vitamin D deficiency defined as?
< 20 ng/mL (target is 30-60 ng/ml) - nanograms per milliliter
Vitamin D toxicity can be caught early, what are the s/sx of early vs late?
Early = CNS + GI issues
Late = Kidney fx affected (nocturia, proteinura, polyuria)
Decalcification of bone and ultimately death
Calcitonin-salmon is used for what? MOA? Admin?
Form of calcitonin derived from salmon
Admin - intranasal spray
Use - Hypercalcemia, osteoporosis, Paget dz
MOA - Inhibits osteoclasts (pulling from bone) and tubular resorption of calcium (excretes Ca++)
What should we identify as a risk for the use of Calcitonin-salmon nasal inhalant?
Limit use d/t possibility of malignancy
Bisphosphonates do what? Used for? A/e?
Inhibit bone resorption by decreasing osteoclast activity.
Osteoporosis, paget dz, hypercalcemia
Esophagitis which can lead to ulcerations (d/t excessive destruction of the hydrophobic layer of the GI tract allowing gastric acid to reach the epithelium)
Bisphosphonates - Alendronate is given?
PO taken aside from food d/t risk of poor absorption (none will be absorbed if taken w/ food)
A/e - same as before; esophageal ulceration
Raloxifene is what? Used for?
Is a selective estrogen receptor modulator (SERM) and is used for postmenses osteoporosis, breast cancer
When estrogen levels decline, it can cause bone resorption, and estrogen replacement can suppress resorption
Teriparatide is a form of PTH. What is it used for? A/e?
Only drug that increases bone formation by increasing serum calcium and lowerng serum phosphate
Tx of osteoporosis
BBW - osteosarcoma (cancer)
PTH and Osteoporosis Treatment:
In some cases, PTH analogs, like teriparatide, are used to treat osteoporosis, but they are administered intermittently to stimulate bone formation rather than resorption.
These analogs work by activating the PTH receptor on osteoblasts, which are bone-forming cells, and inducing bone formation.
They can increase bone density and reduce the risk of fractures, especially in individuals with high fracture risk.
Denosumab is used for what? MOA? Major A/e?
Osteoporosis, tx for anticancer tx bone loss, bone metastases
MOA - decrease ostecloast fx thereby decreasing bone resorption
A/e - osteonecrosis of the jaw (ONJ), infx, hypocalcemia
What is the most common disorder of calcium metabolism? How do we diagnosis?
Osteoporosis (low bone mass and bone fragility)
Dx - Bone mineral density measurer (BMD) or xray
