Ch. 79- Drugs Affecting Calcium + Bone Mineralization Flashcards
What is the total serum calcium level in the body?
10 mg/dL
Where is more than 98% of calcium stored in the body?
In the bones
What hormone increases calcium absorption in the small intestine?
Parathyroid hormone (PTH) and vitamin D
Which hormone decreases calcium absorption?
Glucocorticoids
What hormone is released when calcium levels in the blood rise too high?
Calcitonin
How does calcitonin lower calcium levels in the blood?
- Inhibiting resorption of calcium from bone
- Increasing calcium excretion by the kidney
What are common symptoms of hypercalcemia?
Often asymptomatic, but can involve kidneys, GI tract, and CNS
What are some causes of hypercalcemia?
- Cancer
- Hyperparathyroidism
- Vitamin D intoxication
- Sarcoidosis
- Use of thiazide diuretics
What drugs are used to lower calcium levels in hypercalcemia?
- Inorganic phosphates
- Edetate disodium (EDTA)
- Glucocorticoids
- Calcitonin
- Bisphosphonates
- Gallium nitrate
What is a common clinical presentation of hypocalcemia?
Tetany, convulsions, and spasm of the pharynx
What causes hypocalcemia?
- Deficiency of PTH, vitamin D, or dietary calcium
- Chronic renal failure
- Long-term use of certain medications
What is the treatment for hypocalcemia?
- Calcium supplementation (calcium gluconate-IV, then calcium citrate)
- Vitamin D if there is a coexisting deficiency
What is rickets and who is it usually seen in?
Insufficient dietary vitamin D or limited exposure to sunlight, usually seen in children
What is osteomalacia?
Adult counterpart of rickets, characterized by insufficient vitamin D and impaired mineralization of bone
What is osteoporosis?
Most common disorder of calcium metabolism, characterized by low bone mass and increased bone fragility
What is the cause of primary hyperparathyroidism?
Usually results from a benign parathyroid adenoma
What is the treatment for secondary hyperparathyroidism?
- Vitamin D sterol (paricalcitol)
- Calcium-containing phosphate-binding agents
- Cinacalcet [Sensipar]
What are bisphosphonates used for?
To inhibit bone resorption by decreasing activity of osteoclasts
What is teriparatide?
A form of PTH, the only drug for osteoporosis that increases bone formation
What are the adverse effects of denosumab?
- Hypocalcemia
- Serious infections
- Dermatologic reactions
- Osteonecrosis of the jaw (ONJ)
What is the key diagnostic tool for osteoporosis?
Dual-energy x-ray absorptiometry (DEXA)
What should patients taking calcium avoid?
Spinach
What medication should be prescribed for a patient with hyperparathyroidism and a calcium level of 13.2 mg/dL?
Salmon calcitonin [Calcimar]
Fill in the blank: The preferred parenteral preparation of calcium is _______.
Calcium gluconate
True or False: Vitamin D deficiency is defined as below 20 ng/mL.
True
What is the target level for vitamin D?
30 to 60 ng/mL
