Calcium Metabolism- Abbreviated

Question 1

Vitamin D (aka Calcitriol, Doxercalci-ferol, 1A-Hydroxycalciferol, Calcipotiol, Paricalcitol)- Mech of Action

Answer 1

increase Ca and PO4 absorption from the GI= leads to more bone mineralization

At times when Ca is low:
increases bone resorption (activation of osteoblasts= RANK-L–> osteoclast activation, Osteocalcin–> osteoblast differentiation)

Question 2

Calcimimetics- Available Drugs

Answer 2

Cinacalcet

Question 3

Cinacalcet- Mech of Action

Answer 3

activates Ca sensing receptor (CaR)–> activation of CaR inhibits PTH release

Question 4

Cinacalcet- Clinical Use

Answer 4

secondary hyperparathyroidism
parathyroid carcinoma
chronic kidney disease

Question 5

Cinacalcet- Adverse Effects/Contraindications

Answer 5

hypocalcemia

Question 6

Cinacalcet- Drug Rxns

Answer 6

cyp interactions
levels are increased by Ketoconazole, itraconazole, erythromycin
can increase levels of desipramine

Question 7

Calcitonin- Mech of Action

Answer 7

oppose the actions of PTH
decrease intestinal Ca absorption
increase urinary excretion of CA
DIRECTLY INHIBITS OSTEOCLAST ACTIVITY-->decrease bone resorption
all decrease serum Ca

Question 8

Estrogen- Mech of Action

Answer 8

inhibit action of PTH at bone?

decrease serum PO4= increase active form of Vit. D

Question 9

Estrogen- Clinical Use

Answer 9

osteoporosis in postmenopausal women

combine w/ progestin to reduce risk of carcinoma

Question 10

Estrogen- Adverse Effects/Contraindications

Answer 10

hot flashes, DVT, etc.

increased risk of endometrial carcinoma

Question 11

Potency of D vitamins

Answer 11

Vitamin D3 (aka Cholecalciferol) < 25-Hydroxy D < 1,25-di-Hydroxy D