GI: VITAMIN C+D

Question 1

VITAMIN C+D: INDICATIONS

Answer 1

• Osteoporosis
• CKD
• Severe Hyperkalaemia
• Hypocalcemia
• Vit D Deficiency

Question 2

VITAMIN C+D: MOA

Answer 2

• Calcium homeostasis is controlled by parathyroid hormone and vitamin D, which increase serum calcium levels and bone mineralisation, and calcitonin which reduces serum calcium levels
• In osteoporosis there is a loss of bone mass which increases the risk of fracture
• Restoring positive calcium balance either by dietary means or by administering calcium and vitamin D may reduce the rate of bone loss
• In severe chronic kidney disease, impaired phosphate excretion and reduced activation of vitamin D cause hyperphosphataemia and hypocalcaemia
• This stimulates secondary hyperparathyroidism, which leads to a range of bone changes called renal osteodystrophy.
• In hyperkalaemia, calcium raises the myocardial threshold potential, reducing excitability and the risk of arrhythmias. It has no effect on the serum potassium level.

Question 3

VITAMIN C+D: ADVERSE EFFECTS

Answer 3

• Calcium = dyspepsia and constipation

- Given IV for HYPERK, cardio collapse and local tissue damage

Question 4

VITAMIN C+D: WARNINGS

Answer 4

• Avoid in hypercalcemia

Question 5

VITAMIN C+D: interactions

Answer 5

• Oral calcium reduces the absorption of many drugs including iron, bisphosphonates, tetracyclines and levothyroxine
• IV Calcium should not be mixed with sodium bicarbonate

Question 6

VITAMIN C+D: EXAMPLES

Answer 6

• calcium carbonate
• calcium gluconate
• colecalciferol
• alfacalcidol