Pharm Drugs That Affect Bone Mineral Homeostasis

Front 1

Question: What drug is routinely added to calcium supplements and milk for the purpose of preventing rickets in children and osteomalacia in adults?

Back 1

Cholecalciferol and ergocalciferol

Front 2

Question: What drug is most useful for the treatment of hypercalcemia in Paget's disease?

Back 2

Bisphosphonates (such as pamidronate) and calcitonin are first-line treatments.

Front 3

Question: The active metabolites of vitamin D act through nuclear receptor to produce what effect?

Back 3

Increases Ca and phosphate uptake from the GI, increases bone resorption, and decreases renal excretion of both electrolytes.


Note: They inhibit PTH formation.

Front 4

Question: What is a condition is indicated for the use of raloxifene?

Back 4

Postmenopausal osteoporosis

Front 5

Question: What drug is likely to contribute to osteoporosis after prolonged use?

Back 5

Glucocorticoids.

Front 6

Question: If a PT is started on alendronate, she would be advised to drink large quantities of water with the tablets and remain in the upright position for at 30 minutes and until eating the first meal of the day. By doing so, would decrease what SE?

Back 6

Erosive esophagitis. They can irritate the esophagus and stomach.

Front 7

Question: A nasal spray that contains a protein that inhibits bone resorption, contains what drug?

Back 7

Calcitonin

Front 8

Question: What drug is most likely to lower PTH concentrations that is secondary to chronic kidney disease?

Back 8

Calcitriol, the 1,25-dihydroxyvitamin D

Front 9

Question: What is a vitamin D analog that is used to suppress PTH with less risk of hypercalcemia?

Back 9

Paricalcitol, which is an analogy of 1,25-dihydroxyvitamin D (calcitriol) that lowers serum PTH but rarely precipitate hypercalcemia.

Causes less hypercalcemia and less hypercalciuira than calcitriol.

Front 10

Question: In the treatment of secondary hyperparathyroidism due to chronic kidney disease, cinacalcet is an alternative to vitamin D-based drugs. What is the MOA of cinacalcet to lower PTH?

Back 10

Activating the calcium-sensing receptor in parathyroid cells.

Front 11

What is PTH MOA in the kidney, bone, and intestine?

Back 11

Kidney: Increases reabsorption of Ca and Mg, increases excretion of phosphate, stimulates production of active vitamin D metabolites.

Bone: promotes bone turnover by stimulating osteoblast formation of RANK ligand (RANKL) that stimulates activity of mature osteoclasts.

Intestine: increases absorption of Ca by its activation of vitamin D that occurs in the kidney by upregulating alpha-1 hydroxylase.

Front 12

In high PTH concentration, as in hyperparathyroidism, what is the net effect? What about in low PTH concentration, and what drug acts to do so and its benefit?

Back 12

High PTH (as in primary hyperparathyroidism): increase bone resorption, hypercalcemia, hyperphosphatemia.

Low PTH: net increase in bone formation, which is the bases of teriparatide, a recombinant form of PTH for osteoporosis.

Front 13

What activates and inhibits PTH secretion?

Back 13

Activation: drop in free Ca.

Inhibition: active metabolites of vitamin D.

Front 14

What is UV light action on the skin for vitamin D synthesis? Where can vitamin D2 and D3 be derived from?
What are the active metabolites of vitamin D and where are they found?

Back 14

Vitamin D can by synthesized from 7-dehydrocholesterol in the skin by UV or absorbed in the diet (vitamin D3, cholecalciferol) or plant form (D2, ergocalciferol).

Active metabolites:
Liver: 25-hydroxyvitamin D or calcifediol.

Kidney: 1,25-dihydroxyvitamin D or calcitriol

Front 15

Renal synthesis of active metabolite of vitamin D is stimulated and inhibited by?

Back 15

Stimulated: PTH and fibroblast growth factor 23 (FGF23), a factor produced by osteoblasts and osteoclasts.

Inhibited: by phosphate and vitamin D

Front 16

Active vitamin D causes a net increase in?

How does vitamin D inhibit PTH directly and indirectly?

Back 16

Ca and phosphate by increasing intestinal absorption, bone resorption, and decreasing renal excretion.

By increasing serum Ca

Front 17

When is the active form of vitamin D, calcitriol required to be administered?

Back 17

In conditions that impair vitamin D activation: chronic kidney and liver disease, hypoparathyroidism.

Also in secondary hyperparathyrodism from kidney failure, calcitriol reduces PTH levels, corrects hypocalcemia, improves bone disease, but it can also result in hypercalcemia through direct effects on intestinal, bone, and renal handling of Ca and phosphate.

Front 18

What's the main toxicity of vitamin D?

Back 18

Hypercalcemia, hyperphosphatemia, and hypercalciuria

Front 19

What is the MOA of calcitonin? What is it used for?

Back 19

Decreases serum Ca and phosphate by inhibiting bone resorption and inhibiting renal excretion

To reduce serum calcium for Paget's disease and hypercalcemia. Is used for osteoporosis and to increase bone mass and reduce spine fracture.

Front 20

What is more effective, calcitonin versus triparatide and bisphosphonates?

Back 20

Teriparatide and bisphosphonates.

Front 21

Estrogen and raloxifene (selective estrogen receptor modulator) can delay bone loss in postmenopausal women by?

Back 21

Inhibition of PTH-stimulated bone resorption.

Front 22

Glucocorticoids have a common cause of what on bones?

Back 22

Osteoporosis.

Front 23

What are the bisphosphonates? MOA?

Back 23

Alendronate, etidronate, pamidronate, risedronate.

Inhibit osteoclast activity; decrease osteoclastic bone formation and resorption of hydroxyapatite

Front 24

What is bisphosphonates used for?

Back 24

Malignancy-associated with hypercalcemia, Paget's disease of bone, postmenopasual osteoporosis, multiple myeloma.

Esophageal erosions; osteonecrosis of the jaw

Front 25

What is cinacalcet MOA? What is it used for? SE?

Back 25

Lowers PTH by activating calcium-sensing receptor in the parathyroid gland.

Hyperparathyroidism.

Hypocalcemia, adynamic bone, a condition of profoundly decreased bone cell activity.

Front 26

What is added to drinking water and toothpaste to reduce dental caries?

Back 26

Fluoride.

Front 27

What occurs in renal osteodystrophy

Back 27

In renal failure, there is retention of phosphate that stimulates PTH; also, lack of alpha-1 hydroxylase causes hypocalcemia that stimulates hypocalemia; and metabolic acidosis stimulates bone resorption.