Drugs Affecting Calcium Balance Question And Answers

Drugs Affecting Calcium Balance

Question 1. Write Short Note On Hypercalcemia.
Answer:

Hypercalcemia is the increase in the plasma calcium level above 11 mg/dl.

Various hypercalcemic states are hyperparathyroidism, hypervitaminosis D, osteolytic bony metastasis, and hypercalcemia of malignancy.

• Calcitonin acts directly on bone and inhibits osteoclasts of bone and decreases resorption of bone, decreasing plasma calcium. Calcitonin 4-8 IU/ kg IM 6—l2 hourly only for 2 days should be given in hypercalcemia.
• Calcitonin acts rapidly within 4 hours and the response peaks at 48 hours and then refractoriness develops. Calcitonin also relieves bone pain.
• For emergency treatment of hypercalcemia, 5-10 IU/ kg may be diluted in 500 ml saline and infused IV, over 6 hours.
• Calcitonin is a relatively weak hypocalcemic drug. So it is used only to supplement bisphosphonates initially because bisphosphonates take 24 to 48 hours to act.
• Severe hypercalcemia, a common complication of malignancy, is a medical emergency with altered consciousness. Pamidronate (60-90 mg IV over 2-4 hours) or zoledronate (4 mg IV over 15 min) are the most effective drugs, but take 24 to 48 hours to act.
  They may be supplemented by IM calcitonin 6-l2 hourly for 2 days to achieve rapid action. Vigorous IV hydration is instituted first. After volume repletion, furosemide is added to enhance calcium excretion and prevent volume overload. This is followed by bisphosphonate infusion.
  This therapy reduces serum calcium within a few hours and corrects the attending dehydration. Oral bisphosphonates are not useful. Corticosteroids also lower plasma calcium, but are slow to act, taking l to 2 weeks.

Read And Learn More: Pharmacology Question And Answers

• Gallium nitrate is a potent inhibitor of bone resorption and acts by depressing the ATP-dependent proton pump at the ruffled membrane of osteoclasts.
  Indicated in resistant cases of hypercalcemia. It is given by continuous IV infusion daily for 5 days. It is nephrotoxic and only a reserve drug.
• Glucocorticoids: High doses of prednisolone enhance calcium excretion, decrease calcium absorption and have an adjuvant role in hypercalcemia
  because of lymphoma, myeloma, leukemia, breast carcinoma, etc.