Most Common Salts: Calcium Carbonate and Calcium Citrate
Indications: osteoporosis, heartburn, hyperphosphatemia in renal disease
Dose:
-1 g of calcium carbonate gives 400 mg elemental calcium (40%) and should be taken with food for optimal absorption.
-1 g of calcium citrate gives 210 mg elemental calcium (21%) and can be taken with or without food. Since the elemental calcium percentage is lower than calcium carbonate, patients will have a greater pill burden due to more tablets being taken.
-split dosing should be considered for doses above 500 mg elemental calcium to enhance absorption
-may consider vitamin D to enhance calcium absorption if used for supplementation
Adverse Effects:
-constipation - drink lots of water
-kidney stones (another reason to drink more water)
-gastrointestinal upset and bloating (take with food)
-hypercalcemia when too much is taken
Drug Interactions:
-calcium and iron supplements should be ideally spaced apart so to prevent interfering with each other’s absorption
-tetracyclines, fluoroquinolones, levothyroxine - calcium supplements can chelate and bind to these medications, resulting in decreased absorption
-drugs that decrease acidity (proton pump inhibitors) - may decrease the absorption of calcium carbonate