Calcium Metabolism

Question 1

Vitamin D- Calcitriol, Doxercalci-ferol, 1AHydroxycalciferol, Calcipotiol, Paricalcitol- Mech of Action

Answer 1

INCREASE CA AND PO4 ABSORPTION FROM TEH GI–> LEADS TO BONE MINERALIZATION

INCREASE BONE RESORPTION IF DIETARY CA INTAKE IS LOW (ACTIVATION OF OSTEOBLASTS= RANK-L–> OSTEOCLAST ACTIVATION, OSTEOCALCIN–>OSTEOBLAST DIFFERENTIATION)

Question 2

Vitamin D- Calcitriol, Doxercalci-ferol, 1AHydroxycalciferol, Calcipotiol, Paricalcitol- - Clinical Use

Answer 2

prophylaxis and cure of nutritional rickets
treatment of metabolic rickets and osteomalacia in chronic renal failure
treatment of hypoparathyroidism
prevention and treatment of osteoporosis
calcipotiol used topically for psoriasis
paricalcitol given IV for secondary hyperparathyroidism

Question 3

Vitamin D- Calcitriol, Doxercalci-ferol, 1AHydroxycalciferol, Calcipotiol, Paricalcitol- Adverse Effects/Contraindications

Answer 3

the side effects of hypercalcemia

Question 4

Vitamin D- Calcitriol, Doxercalci-ferol, 1AHydroxycalciferol, Calcipotiol, Paricalcitol- Drug Rxns

Answer 4

estrogen, Idonazide, Thiazide diuretics increase levels of Vit D. (desirable in estrogen for osteoporosis)

Ca channel blockers may decrease Vit D synthesis

Phenobarbital and Phenytoin increase Vit D metabolism

Long term antacids alter metabolism/bioavailability of Vit D

Question 5

Recombinant Human PTH- Teriparatide- Mech of Action

Answer 5

increase kidney tubular reabsorption of CA

increase production of active Vit D

increase Ca release from bone

if given intermittently stimulates bone deposition

Question 6

Recombinant Human PTH- Teriparatide- Clinical Use

Answer 6

Severe osteoporosis

combination with Alendronate gives synergistic effect

Question 7

Recombinant Human PTH- Teriparatide- Adverse Effects/Contraindications

Answer 7

osteosarcoma in animals

Contraindicated in history of osteosarcoma and Paget’s disease

not approved for use in children

Question 8

Calcimimetics- Cinacalcet- Mech of Action

Answer 8

ACTIVATES CA SENSING RECEPTOR (CAR)–> ACTIVATION OF CAR INHIBITS PTH RELEASE

Question 9

Calcimimetics- Cinacalcet- Clinical Use

Answer 9

SECONDARY HYPERPARATHYROIDISM
PARATHYROID CARCINOMA
CHRONIC KIDNEY DISEASE

Question 10

Calcimimetics- Cinacalcet- Adverse Effects/Contraindications

Answer 10

HYPOCALCEMIA

Question 11

Calcimimetics- Cinacalcet- Drug Rxns

Answer 11

CYP INTERACTIONS
LEVELS ARE INCREASED BY KETOCONAZOLE, INTRACONAZOLE, ERYTHROMYCIN

CAN INCREASE LEVELS OF DESIPRAMINE

Question 12

Gallium Nitrate- Mech of Action

Answer 12

decrease bone resorption

Question 13

Gallium Nitrate- Clinical Use

Answer 13

hypercalcemia associated w/ malignancy

Question 14

Gallium Nitrate- Adverse Effects/Contraindications

Answer 14

nephrotoxicity- keep well hydrated

Question 15

Gallium Nitrate- Drug Rxns

Answer 15

extremely extensive drug interactions

Question 16

Glucocorticoids- Hydrocortisone- Mech of Action

Answer 16

antagonize actions of Vit D: decrease intestinal Ca absorption

increase renal excretion of Ca

Question 17

Glucocorticoids- Hydrocortisone- Clinical Use

Answer 17

Vit D intoxication
Hypercalcemia of malignancy

NOT effective in PTH induced hypercalcemia

Question 18

Glucocorticoids- Hydrocortisone- Adverse Effects/Contraindications

Answer 18

long term treatment can cause osteoporosis (intermediate treatment only) and suppression of the hypothalamic-adrenal axis

Question 19

Thiazides- Mech of Action

Answer 19

increase renal reabsoption of Ca in distal convoluted tubule–> prevent stone formation

Question 20

Thiazides- Clinical Use

Answer 20

renal hypercalciuria

Question 21

Bisphosphonates: Etidronate, Pamidronate, Alendronate, Risendronate, Tiludronate- Mech of Action

Answer 21

structurally similar to pyrophosphate–> have a high affinity for Ca–> adsorb to bone crystal, making it resistant to hydrolysis

also inhibit production of active Vit D

Question 22

Bisphosphonates: Etidronate, Pamidronate, Alendronate, Risendronate, Tiludronate- Clinical Use

Answer 22

Paget’s Disease
osteoporosis (Alendronate, Risendronate, Ibandronate)- useful in women who cannot tolerate estrogen

hypercalcemia of malignancy

all administered PO except Pamidronate= injected

Question 23

Bisphosphonates: Etidronate, Pamidronate, Alendronate, Risendronate, Tiludronate- Adverse Effects/Contraindications

Answer 23

bone pain, GI-dyspepsia, anorexia, esophageal ulceration, hypocalcemia, hypophosphatemia

Contraindicated in children, pregnancy, breast feeding, GI ulcers, impaired renal function

Question 24

Bisphosphonates: Etidronate, Pamidronate, Alendronate, Risendronate, Tiludronate- Drug Rxns

Answer 24

AL(OH)3, antacids, Ca, Mg, Fe salts all decrease absorption of orally administered drugs

NSAIDS- increased incidence of GI ulcers
No drug rxns w/ Palmidronate

Question 25

Fluoride- Mech of Action

Answer 25

mitogen for osteoblasts to stimulate bone formation

rapidly absorbed- stored in bone and teeth

Question 26

Fluoride- Adverse Effects/Contraindications

Answer 26

dental fluorosis
dermatitis
GI bleeding
nausea
vomiting
stomatitis
urticaria

caution in arthralgia, pregnancy, nursing, children

Question 27

Estrogen- Mech of Action

Answer 27

INHIBIT ACTION OF PTH AT BONE?

DECREASE SERUM PO4–> INCRASE ACTIVE FORM OF VIT D

Question 28

Estrogen- Clinical Use

Answer 28

OSTEOPOROSIS IN POST-MENOPAUSAL WOMEN

COMBINE W/ PROGESTIN TO REDUCE RISK OF CARCINOMA

Question 29

Estrogen- Adverse Effects/Contraindications

Answer 29

HOT FLASHES, DVT, ETC.

INCREASED RISK OF ENDOMETRIAL CARCINOMA

Question 30

SERMS- Raloxifene- Mech of Action

Answer 30

Estrogen agonist in bone

Estrogen antagonist in breast and uterus

Question 31

SERMS- Raloxifene- Clinical Use

Answer 31

osteoporosis in postmenopausal women

osteoporosis in pre-menopausal women

Question 32

SERMS- Raloxifene- Adverse Effects/Contraindications

Answer 32

hot flashes, DVT, etc.

Contraindicated in pregnancy, breastfeeding

Question 33

Potency of D Vitamins

Answer 33

Vit D3/Cholecalciferol< 25-Hydroxy D< 1,25-di-Hydroxy D