Term
| What are the 3 main hormones involved in calcium homeostasis? |
|
Definition
PTH - hypercalcemic
Vitamin D - hypercalcemic
Calcitonon - hypocalcemic
(Hypercalcemic : increase Ca in body when there is a decrease, Hypocalcemic : decrease Ca levels when there is excess) |
|
|
Term
| What is the process of homeostasis when there is a fall in Ca levels? |
|
Definition
PTH is released from parathyroid glands
- Stimulates Ca release from bones
- Stimulates Ca reabsorption from kidney
- Stimulates the formation of calcitriol (which is the active form of Vit D) |
|
|
Term
| What is the process of homeostasis when there is an increase in Ca levels in the body? |
|
Definition
Calcitonin is released from the THYROID gland
- Ca deposition in the bone is simulated
- Reduces Ca reabsorption in the kidney
- Reduces Ca reabsorption in the intestine |
|
|
Term
What is Teriparatide?
Use? |
|
Definition
| Recombinant form of the PTH - used in osteoporosis |
|
|
Term
What are the symptoms associated with Hyperparathyroidism?
How is this treated? |
|
Definition
Hypercalcemia
Decalcification of bone
Renal stones
Muscle weakness
constipation & anorexia
Tx - SURGERY
|
|
|
Term
What cell in the body is involved with bone reabsorption
Which cell is involved in bone formation |
|
Definition
- Osteoclast - Bone reabsorption
- Osteoblast - Bone formation |
|
|
Term
| When is Calcitonin used as treatment, what is the name of the drug? |
|
Definition
Synthetic calcitonin - Salmon
Hypercalcenmic states
Postmenopausal osteoporosis |
|
|
Term
| What is the process of activation of Vit D? |
|
Definition
Cholecalciferol (Vit D3)- In the skin under the presence of UV
In the liver is converted to - 25 - Hydroxycholecalciferol (25-hydroxy Vit D3)
In the kidney is converted to - 1, 25 - dihydroxycholecalciferol (1,25 - dihydroxy - Vit D3) ** active form** |
|
|
Term
|
Definition
Increases synthesis of Calcibindin - carrier protein for Ca (aka Ca binding protein)
Stimulates recruitment & differentiation of osteoclast - for bone reabsorption |
|
|
Term
| What are the disorders associated with Vit D? |
|
Definition
Hypovitaminosis:
Rickets in children, Osteomalacia in adults
Hypervitaminosis:
Hypercalcaemia, weakness, fatigue
Treatment includes low Ca diet, lots of fluid intake, glucocorticoids
|
|
|
Term
| What are the Vit D preparations available? |
|
Definition
Cholecalciferol (D3): oral and i.m injection
Calcitriol: orally
Alfacalcidol; it is alpha -OHD3- a prodrug that is rapidly hydroxylated in the liver to 1,25 (OH)2D3 or clacitriol - Used orally
|
|
|
Term
Bisphosphonates
Drugs?
MOA?
Use? |
|
Definition
|
'Dronate' - Alendronate & Risedronate
- Inhibit recruitment & promote apoptosis of
osteoclasts - thus inhibiting bone reabsorbtion
-Indirectly stimulate osteoblast activity
Pagets disease
Osteoporosis
|
|
|
Term
| What are the ADR's of Bisphosphonates |
|
Definition
Gastrointestinal disturbances
Bone pain
Peptic ulcers
Esophagitis (can be prevented by taking drugs with a glass full of water and in an erect position)
|
|
|
Term
Estrogens
Use
What happens when there is a reduction? |
|
Definition
|
Important role in maintaining bone structure
Inhibit the cytokines that recruit osteoclasts and oppose the Ca2+-mobilising action of PTH
Reduction in oestrogen can lead to osteoporosis
|
|
|
Term
Selective estrogen receptor modulators (SERM's)
Drug?
MOA?
ADR? |
|
Definition
Raloxifene
Agonist activity in bone and CVS
Antagonist activity in mammary tissue and uterus
Increases osteoblast activity and decreases osteoclast activity
ADR: hot flushes, leg cramps, venous thromboembolism
|
|
|
Term
Name the Calcium salts
Use?
ROA?
ADR? |
|
Definition
Calcium gluconate & calcium lactate
dietary deficiency
hypocalcaemia caused by hypoparathyroidism or malabsorption
Prevention and treatment of osteoporosis
Given orally or by i.v. (gluconate) injection
Can cause GI disturbances
|
|
|
Term
Teriparatide
MOA
Clinical use? |
|
Definition
Recombinant DNA PTH analogue
Once a day to stimulate osteoblasts and new bone formation
** continuous stimulation may stimulate osteoclast activity** |
|
|
