Elemental Calcium Content in Calcium Gluconate
One gram (1000 mg) of calcium gluconate contains approximately 90-93 mg of elemental calcium, which represents about 9% elemental calcium content. 1, 2, 3
Precise Dosing Information
- A standard 10-mL ampule of 10% calcium gluconate solution contains 1 gram of calcium gluconate, which provides 90 mg of elemental calcium 1, 2
- The FDA-approved formulation specifies that calcium gluconate injection contains 100 mg of calcium gluconate per mL, which contains 9.3 mg (0.465 mEq) of elemental calcium 3
- This means calcium gluconate is 9-9.3% elemental calcium by weight 2, 3
Clinical Calculation Example
For practical dosing calculations:
- 1 gram calcium gluconate = 90-93 mg elemental calcium 2, 3
- 10 grams calcium gluconate = 900-930 mg elemental calcium 2, 3
Comparison with Other Calcium Salts
Understanding relative elemental calcium content is essential for appropriate substitution:
- Calcium carbonate: 40% elemental calcium (highest concentration) 1, 2
- Calcium acetate: 25% elemental calcium 2
- Calcium citrate: 21% elemental calcium 1
- Calcium lactate: 13% elemental calcium 2
- Calcium gluconate: 9% elemental calcium (lowest concentration among common preparations) 2, 3
Clinical Implications
- Calcium chloride contains significantly more elemental calcium than calcium gluconate and is preferred in emergency situations such as cardiac arrest, severe hyperkalemia, or critical hypocalcemia 4
- When treating post-parathyroidectomy hypocalcemia with calcium gluconate infusions, dosing is based on elemental calcium at 1-2 mg/kg/hour, requiring calculation from the total calcium gluconate dose 1, 2
- For oral supplementation requiring higher elemental calcium doses, calcium carbonate is more practical due to its 40% elemental calcium content 1