From the Guidelines
The recommended dose of calcium carbonate for hypocalcemia in dialysis patients is 500-1000 mg elemental calcium 2-3 times daily with meals. This recommendation is based on the most recent and highest quality study available, which suggests that patients with significant or symptomatic hypocalcemia could still benefit from correction to prevent adverse consequences 1.
Key Considerations
- Oral calcium supplements such as calcium carbonate or calcium acetate may be prescribed to manage hypocalcemia in dialysis patients.
- Active vitamin D analogs like calcitriol, paricalcitol, or doxercalciferol are essential as dialysis patients cannot adequately convert vitamin D to its active form due to impaired kidney function.
- Phosphate binders are often necessary to control serum phosphate levels, as hyperphosphatemia worsens hypocalcemia.
- Calcimimetics like cinacalcet may need adjustment or temporary discontinuation if they're contributing to low calcium levels.
Monitoring and Adjustments
- Regular monitoring of calcium, phosphorus, and parathyroid hormone levels is crucial to guide therapy adjustments.
- Treatment aims to maintain calcium levels within the normal range while avoiding hypercalcemia, which can lead to vascular calcification and increased cardiovascular risk in this vulnerable population 1.
Safety and Efficacy
- The use of calcium-based phosphate binders should be restricted to patients with hyperphosphatemia, as they may cause a positive calcium balance and increase the risk of coronary and aortic calcification 1.
- The addition of calcium carbonate to meals containing calcium and phosphorus may not affect baseline neutral phosphate balance but can cause a positive short-term calcium balance 1.
From the Research
Treatment for Hypocalcemia in Dialysis Patients
The recommended treatment for hypocalcemia (low calcium levels) in dialysis patients involves managing the body's calcium and phosphate balance.
- Dialysate calcium concentration can be adjusted to achieve this balance, with a common concentration used being 1.5 mmol/L 2.
- However, the ideal dialysate calcium level may vary depending on individual patient factors, such as the use of calcium-based phosphate binders or vitamin D supplements 2, 3.
Calcium Supplementation
Calcium supplementation can be used to treat hypocalcemia in dialysis patients.
- A study found that oral calcium supplementation (600 mg twice a day) was effective in resolving secondary hyperparathyroidism in patients with normal kidney function and vitamin D levels 4.
- Another study compared the efficacy of calcium carbonate and calcium acetate as phosphate binders in predialysis patients, finding that both were effective but calcium acetate had a lower hypercalcemic effect 5.
Dialysate Calcium Levels
The choice of dialysate calcium level can have important consequences for dialysis patients.
- Lower dialysate calcium levels (< 2.5 mEq/L) have been associated with an increased risk of sudden cardiac death, while higher levels (3.0 mEq/L and above) may contribute to vascular pathology 3.
- A dialysate calcium level of 2.75 mEq/L may help achieve a net zero intradialytic calcium balance in individual patients, but more research is needed to confirm this 3.
Comparison of Calcium Salts
Studies have compared the efficacy of different calcium salts, such as calcium carbonate and calcium acetate, as phosphate binders in dialysis patients.
- One study found that calcium acetate was more effective than calcium carbonate in controlling serum phosphorus levels, with a lower incidence of hypercalcemia 6.
- Another study found that both calcium carbonate and calcium acetate were effective in controlling serum phosphorus levels, but calcium acetate required a lower dose of elemental calcium 5.