Elemental Calcium Content in 500mg Calcium Carbonate Tablet
A 500mg calcium carbonate tablet contains 200mg of elemental calcium, as calcium carbonate provides 40% elemental calcium by weight. 1
Calcium Carbonate Composition
Calcium carbonate is one of the most commonly used calcium supplements due to its high elemental calcium content and cost-effectiveness. Here's how it compares to other calcium salts:
- Calcium carbonate: 40% elemental calcium 1
- Calcium acetate: 25% elemental calcium 1
- Calcium lactate: 13% elemental calcium 1
- Calcium gluconate: 9% elemental calcium 1
Practical Examples
- A 500mg calcium carbonate tablet provides 200mg of elemental calcium
- A 1250mg calcium carbonate tablet provides 500mg of elemental calcium 2
- A TUMS Ultra™ 1000mg tablet provides 400mg of elemental calcium 1
Clinical Considerations for Calcium Supplementation
Dosing Recommendations
- Maximum recommended single dose of elemental calcium is 500mg for optimal absorption 3
- Calcium carbonate should be taken with meals to ensure optimal absorption 3
- For patients requiring phosphate binding (such as those with CKD), calcium carbonate should be taken with meals for maximal phosphorus-binding efficacy 1
Potential Side Effects
- Common side effects include gastrointestinal complaints such as constipation and bloating 1
- High doses of calcium carbonate (>2.0 g/day) may increase the risk of non-anion gap metabolic acidosis, particularly in patients with CKD 4
Special Populations
- In patients with achlorhydria or those taking histamine-2 blockers or proton pump inhibitors, calcium citrate may be better absorbed than calcium carbonate 3
- For patients with CKD, total calcium intake (dietary + supplements) should be monitored to avoid exceeding recommended limits 1, 4
Calculating Total Daily Calcium Intake
When prescribing calcium supplements, it's important to calculate the total elemental calcium intake:
- Assess dietary calcium intake
- Determine supplemental needs based on recommended daily allowances
- Choose appropriate calcium salt and dosage
- Calculate total elemental calcium from all sources to ensure it doesn't exceed upper intake levels
Remember that calcium carbonate provides the most elemental calcium per tablet weight, making it an efficient choice when higher doses are needed.