1. Drugs for osteoporosis (download the lecture from www.skilltest.co.in)
Dr. Sarvesh Singh
Associate Professor
Dept. of Pharmacology
KGMU, Lucknow d

2. PLASMA CALCIUM LEVEL Regulated by 3 hormones: Parathormone (PTH)
Calcitonin
Calcitriol (active form of vit D) d

3. PARATHORMONE (PTH) Stimulus for secretion of PTH: Fall in plasma Ca2+
Calcium-sensing receptors (CaSR) present on the surface of parathyroid cells. d

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5. ACTIONS OF PTH PTH increases plasma calcium levels by: Bone:
Bone resorption: increases
2. Kidney:
Calcium reabsorption in the distal tubule: increases
3. Intestines:
Calcium absorption increases indirectly
Enhance the formation of calcitriol (active form of vit D)
Calcitriol promotes intestinal absorption of calcium d

6. MECHANISM OF ACTION OF PTH
Mainly on bone:
Bone resorption:
Activation of osteoclast:
Expression of PTH receptors:
PTH receptor is a G protein coupled receptor
Expressed on osteoblasts
Absent on osteoclasts d

7. PTH ACTION ON OSTEOBLAST
PTH receptor located on osteoblast membrane
PTH induces a factor 'Receptor for activation of nuclear factor-KB-ligand' (RANKL)
RANKL diffuses and combines with RANK on osteoclast precursors
PRECURSORS TRANSFORM INTO
OSTEOCLASTS d

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9. TERIPARATIDE RECOMBINANT HUMAN PARATHYROID HORMONE
Approved for the treatment of:
Severe osteoporosis
PTH at high concentration:
Bone resorption predominates
PTH at low concentration with intermittent exposure:
Bone formation predominates
Only agent which stimulates bone formation
Equally or more effective than estrogens and BPNs:
In reducing risk of vertebral as well as non-vertebral fractures d

10. TERIPARATIDE Injected s.c. once daily
Given once daily produces intermittent action
LIMITATIONS:
High cost
Need for daily s.c. injection d

11. Drugs for Osteoporosis
Calcium and Vitamin D3
Bisphosphonates
HRT
Raloxifene- selective oestrogen receptor modulator (SERM) which selectively binds to oestrogen receptors on bone.
Teriparatide- a fragment of recombinant human parathyroid hormone
Calcitonin- Given as a nasal spray of synthetic calcitonin d

12. Bisphosphonates d

13. Bisphosphonates
First line treatment for primary and secondary prevention of osteoporotic fractures
Reduce bone resorption by inhibiting action of osteoclasts
Accelerate apoptosis of osteoclasts
Disruption of cytoskeleton and ruffled border
Most effective antiresorptive drugs
Available orally as daily or weekly tablet, or as a yearly injection
Daily and weekly- alendronate, risedronate
Yearly IV- zoledronate infusion d

14. Side Effect
Oesophageal irritation/ ulceration if insufficient water taken with tablet or lie down after taking d

15. Download the lecture from www.skilltest.co.in

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18. Thank you d