drugs that affect calcium metabolism and bone turnover

Question 1

parathyroid

Answer 1

stimulated by low Ca levels, leads to increased Ca and Vit D

Question 2

calcitonin

Answer 2

stimulated by high Ca,, leads to decreased Ca

Question 3

osteoclasts vs osteoblasts

Answer 3

clasts contribute to bone resorption or breakdown; blasts contribute to bone deposition or formation

Question 4

vitamin D

Answer 4

-increases absorption of Ca from GI tract and increases the amount of Ca from bone –> serum; decreases excretion of Ca in urine

Question 5

effects of glucocorticoids on calcium homeostatis

Answer 5

-decreased absorption from GI tract, increased resorption from bone

Question 6

ergocalciferol vs calcitriol

Answer 6

ergo is D2, calcitriol is d3

-associated with better prostate and breast health

Question 7

bisphonphonate MOA

Answer 7

• taken up by osteoclasts, etidronate retards the dissolution of hydroxyapatite (main component of bone)
• inhibitors of geranylgeranyl diphosphate synthase, an enzyme involved in isoprenoid biosynthesis, leads to inhibition of bone resoprtion

Question 8

bisphosphonate names

Answer 8

alendronate, risedronate, ibandronate and zolendronate (oral)
ibandronate and zoledronate (IV)

Question 9

SE of bisphosphonates

Answer 9

• poor absorption orally and may induce esophagitis

- osteonecrosis of jaw

Question 10

denosumab

Answer 10

-antibody that inhibits bone resorption by binding to RANKL, thus preventing its binding to RANK, a receptor present in osteoclasts that stimulates their activity. injectible

Question 11

teriparatide

Answer 11

• PTH
• when given at low doses on a daily basis, acts on osteoblasts to stim bone formation
• nasal spray
• only drug that stim new bone development

Question 12

rx of hypocalcemia

Answer 12

-calcium salts to increase ca uptake and vitamin D to increase ca absorption

Question 13

rx of hypercalcemia

Answer 13

calcitonin and bisphosphonates to prevent bone resoprtion