Drugs affecting calcium balance Flashcards
What are the effects of PTH?
Bone- Net increase in resorption and Increases Calcium
Kidney- Increases calcium, ↓reabsorption of phosphate and Stimulates Vitamin D to active form
Intestine- Indirectly increases Calcium and phosphate absorption by enhancing formation of vit D3 (active form) in kidney.
What are the actions of Vit D?
Increases calcium
Increases bone turn over
Renal- Increased calcium absorption in distal tubules and
Increased Phosphate absorption.
What are the actions of Calcitonin?
Potent inhibitor of osteoclast mediated bone resorption
Decreases renal excretion of Ca2+
Plasma Phosphorus concentration lowered
What is MoA of teriparatide?
Synthetic human PTH
Continuous use: Bone demineralization, osteopenia
Intermittent use: Bone growth and increases Bone Mineral Density
What is the use of teriparatide?
Used to treat osteoporosis and promotes fracture healing.
What are ADR of teriparatide?
Increased risk of osteosarcoma
Nephrolithiasis
Increased serum uric acid levels (gout)
What is MoA of cinacalcet?
Increases sensitivity of CaSR (Ca sensing receptor) to extracellular Ca2+ leads to decrease in PTH.
What is the use of cinacalcet?
Treats parathyroid carcinoma and secondary hyperparathyroidism.
What are ADR of cinacalcet?
Hypocalcemia
Decreases seizure threshold (Not used if <8.4mg/dl)
What is MoA of denosumab?
Monoclonal antibody
Binds with high affinity to RANKL, mimicking OPG
Blocks osteoclast formation and activation
Increases Bone Mineral Density
What are some Vit D preparations?
Cholecalciferol
Calcitriol
What are some calcium salts?
Calcium gluconate- Given in hypocalcemia, rapid infusion can cause cardiac arrhythmias
Calcium carbonate
What are some bisphosphonates?
Etidronate
Alendronate, pamidronate
Risedronate, zoledronate
What is MoA of bisphosphonates?
Analogs of pyrophosphate
Chelates calcium and sticks it to the bone
Strong affinity for bone, get incorporated in matrix and remain until bone is remodeled
Inhibits recruitment and promote apoptosis of osteoclasts, and inhibit bone resorption by inhibiting farnesyl pyrophosphate synthase
What are ADR of bisphosphonates?
Gastric irritant- given on empty stomach
Osteonecrosis of jaw (also caused by denosumab)
Atypical subtrochanteric fracture (never given after a fracture because healing requires ostoclasts).
What is MoA of Raloxifene?
Selective Estrogen Receptor Modulator
What is the use of Raloxifene?
Used in prevention and treatment of osteoporosis
Increases Bone Mineral density (BMD)
What is MoA of calcitonin?
Decreases Ca2+ levels
What is the use of calcitonin?
Treatment of hypercalcemia, paget’s disease
Can cause allergic reactions
What is Osteoporosis? and treatment
Primary- Loss of trabecular bone
Tx- Bisphosphonates (DOC- Alendronate), Teriparatide
Secondary- Loss of cortical and trabecular bone
Tx- Glucocorticoids
What is paget’s disease? and treatment
Increased bone resorption followed exuberant bone formation, new bone disorganized and of poor quality.
Tx- Bisphosphonates-Alendronate
Calcitonin
Vit. D deficiency and treatment
Adults- Osteomalacia
Children- Rickets
Tx-Vit D daily
What is Hypoparathyroidism and treatment
PTH deficiency- blood calcium level falls and phosphate levels rise
Tx- Dihydrotachysterol
What is Secondary hyperparathyroidism and treatment
Caused by renal failure, kidney excretes less phosphate
High blood phosphate precipitates calcium- forms calcium phosphate, blood calcium decreases and stimulates PTH. Bone resorption is increased
Tx- DOC Cinacalcet
Calcitriol
