drug affecting Ca balance Flashcards
bone formation
osteoblasts
bone resorption
osteoclasts
PTH Ca increase and P decrease
Vit D Ca increase and P increase
Calcitonin Ca decrease
FGF23 P decrease
Net serum level
Plasma Ca increase
plasma phosphate decrease
Effects on bone - demineralization and osteopenia
primary hyperparathyroidism
Plasma Ca decrease
plasma phosphate increase
Effects on bone - malformation
primary hypoparathyroidism
Plasma Ca decrease
plasma phosphate decrease
Effects on bone - osteomalacia and Ricketts
vit D def
Plasma Ca increase
plasma phosphate increase
Effects on bone - osteoporosis
excess vit D
Plasma Ca decrease
plasma phosphate increase
Effects on bone - osteomalacia and osteosclerosis
renal failure + high plasma phosphate
in adequate diet and hypoparathyroidism
tx with Vit D and calcium
hypocalcemia
hyperparathyroidism and hypervitaminosis D
Tx: 1) loop diuretics + IV fluids, bisphosphonates, calcitonin, glucocorticoids, low calcium diet
hypercalcemia
pagets dz of the bone and osteoporosis
tx for pagets: bisphosphonates and calcitonin
tx for osteoporosis: bisphosphonates, calcitonin, estrogen, SERMs supplemented with calcium and Vit D
bone remodeling
produced by osteoblasts
fxn: promotes urinary phosphate excretion - PCT; suppression of activated Vit D produced by kidney
fibroblast growth factor 23
1) Ca sensing receptor on parathyroid gland
2) stimulates osteoblasts to release receptor activator of nuclear factor RANKL - activates osteoclasts; RANKL binds to RANK on the osteoclast surface - increasing differentiation and activity - increasing bone resorption
3) increase Ca resorption by the kidney and increase phosphate excretion
4) intestine: indirectly increase Ca and P absorption by enhancing formation of Vit D3 in kidney
PTH - parathyroid hormone
senses increase serum Ca
increase serum Ca levels inhibit PTH production and secretion
Ca sensing receptor on parathyroid hormone gland
increase Ca
absorption by TRPV6 Ca ch in duodenum and proximal jejunum
Vit D - calcitriol
obtained by dairy products or UVB radiation in sunlight
vit D3 cholecalciferol
ergocalciferol obtained by plants
vit D2
found in food
vit D1
stimulates intestinal absorption of Ca and P
stimulates osteoblasts to release RANKL - activates osteoclasts
inhibits PTH production by parathyroid gland
Vit D - calcitriol
increase bone turn over (increase bone formation)
increase bone density
inhibit epidermal proliferation
increase Ca absorption in distal tubules
Vit D - calcitriol
used to tx: osteoporosis, prevent hypocalcemia in chronic kidney dz, psoriasis
Vit D - calcitriol
produced in thyroid - thyroid parafollicular C cells
potent inhibitor of osteoclast mediated bine resorption (decrease)
promotes Ca excretion by the kidney
Used: hypercalcemia, Pagets dz
CI: hypocalcemia
calcitonin
synthetic PTH
increase Ca resorption by the kidney and increase phosphate excretion
increase activity of 1 alpha hydroxyls in kidney - increase production Vit D
teriparatide
Tx: osteoporosis
continuous use: bone demineralization, osteopenia
intermittent use: bone growth <2 yrs duration
ADR: increase risk osteosarcoma, nephrolithiasis, increase S uric acid levels
teriparatide
MOA: increase sensitivity of CaCr to extracellular Ca; activates the Ca sensing receptor on the parathyroid gland - decrease production of PTH
cinacalcet
used to tx: hyperparathyroidism and parathyroid carconoma
ADR: hypocalcemia
cinacalcet
monoclonal antibody
blocks osteoclast formation and activation
increase bone mineral density
mimics OPG
Used: osteoporosis
denosumab
Vit D preparations
1) cholecalciferol - D3
2) calciferol
3) alfacacidol: 1 OH Vit D3 - useful in kidney dysfunction
4) paricalcitol D2
Ca gluconate
Ca chloride
Ca carbonate
calcium salts
chelates Ca
bind to osteoclasts, inhibiting their adherence to the bony surface
decrease the development and recruitment of osteoclast precursors
induce osteoclasts apoptosis
bisphosphonates
inhibit farnesyl pyrophosphate synthase - attach to hydroxyapatite in bone
bisphosphonates
uses: pagets, osteoporosis, acute hypercalcemia
SE: GIT (upper), sit upright 30 min and drink water
can cause osteonecrosis of jaw
hypoglycemia, bone pain and subtrochanteric fracture
bisphosphonates
can not use in renal failure px
bisphosphonates 3 generations
1) etidronate - less potent
2) alendronate, pamidronate
3) risedronate, zoledronate
SERM used to tx and prevent of postmenopausal osteoporosis
increase bone mineral density
estrogen agonist on bone
estrogen antagonist on breast and uterus
raloxifene
DOC for treating hypercalcemia
hydration fluid + furosemide
drugs decreasing bone mineral density
Glucocorticoids
medroxyprogesterone
type 1: loss of trabecular bone - decrease estrogen
type 2: loss of cortical and trabecular bone
osteoporosis
treatments for osteoporosis
1) DOC bisphosphonates
2) raloxifene - women
3) teriparatide - male/women - for sever case; used in fracture healing
tx for pagets
bisphosphonates: alendronate, risedronate, zoledronate
calcitonin
adults - osteomalacia
children - ricketts
vit D def
tx for hypoparathyroidism
1) vit D - DOC with calcium
2) dihydrotachysterol
3) calcitriol
kidney excretes less phosphate
high blood phosphate predicates Ca - forms Ca phosphate - blood Ca decreases - stimulates PTH
secondary hyperparathyroidism in renal failure
PTH >88 bone resorption is increased
tx for hyperparathyroidism
1) DOC - cinacalcet
2) aluminum hydroxide, calcitriol
