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20 Cards in this Set
- Front
- Back
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What can we give to treat osteoporosis?
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Bisphosphonates - first-line treatmentTeriparatideEstrogensTiboloneRaloxifeneDenosumab
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Name bisphosphonates
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Aminobisphosphonates:- Alendronate- Risedronate- Zoledronate
Simple bisphosphonates:- Etidronate |
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Indications for bisphosphonates?
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- Osteoporosis- Hypercalcemia due to tumor-induced osteolysis or multiple myeloma - only zoledronate- Inherited bone diseases
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Mechanism of action of bisphosphonates?
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They are analogues of pyrophosphonate, which inhibits bone resorption, but they are resistant to enzymatic breakdown and laster longer.
They form complexes with calcium in the bone matrix and are released slowly when bone is reabsorbed by osteoclasts, inhibiting osteoclasts. Simple bisphosphonates are incorporated into ATP analogues, they accumulate and cause apoptosis of osteoclasts. Aminophosphonates interfere with attachments of osteoclasts to bone. |
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What should the bisphosphonates be taken orally?
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They should be taken on an empty stomach with plenty of water while sitting or standing for 30 mins before eating. These tablets can cause a lot of problems if they get stuck in the esophagus.
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Where do bisphosphonates accumulate?
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Around 50 % of it accumulates in the bones and remain there for years.
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Adverse effects of bisphosphonates?
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- Bone pain- Esophagitis if not taken correctly- Aseptic ostenecrosis of the jaw (high dose IV administration)
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Contraindiations for bisphosphonates?
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Renal failure and hypocalcemia
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When is teriparatide indicated?
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In osteoporosis when its severe or when bisphosphonates are contraindicated.
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Mechanism of action of teriparatide?
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It is a fragment of parathyroid hormone. Low doses of exogenous PTH or its analogues stimulate osteoblast activity, resulting in new bone formation.
(PTH usually stimulates osteoclasts) |
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How long does therapy with teriparatide last?
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Therapy should not last longer than 24 months and only one period of 24 months is allowed during lifetime.
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Name vitamin D preparations
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Ergocalciferol, alphacalciferol, cholecalciferol
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Which form of vitamin D is synthesized in our skin?
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Cholecalciferol
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Indications for vitamin D preparations?
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- Hypocalcemia due to hypoparathyroidism- Osteodustrophy due to renal failure- Vitamin D deficiency
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Mechanism of action of cholecalciferol?
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It is converted to calcifediol in the liver, which is further converted into calcitriol in the kidney. Its actions are:
- Stimulating intestinal absorption of Ca2+ and phosphate- Stimulating bone resorption- Stimulating Ca2+ reabsorption in the kidneys |
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What is necessary for absorption of vitamin D preperations?
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Bile salts
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What are the adverse effects of vitamin D preparations?
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Hyperglycemia - GI symptoms, abdominal pain and kidney stones (ouch)
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Indications of denosumab?
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- Osteoporisis when there is high risk for fracture.- Prevention of fracture in patients with bone metastases from solid tumors
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Mechanism of action of denosumab?
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It is a monoclonal antibody which binds to RANK ligand (RANKL), which is the primary signal for bone resorption found in osteoblasts to stimulate osteoclasts. Denosumab inhibits this mechanism
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Can we use estrogens and raloxifene for treatment of osteoporosis? Why/why not?
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Estrogen is not first-line treatment as it increases risk for cancer and cardiovascular disease.
Raloxifene has same positive effects as estrogen on osteoporosis, and does not increase risk of cancer and cardiovascular disease. It increases the risk of thrombus though. It is often used in patients who need breast cancer prophylaxis |
