From the Guidelines
Phosphate supplements can cause significant side effects, particularly hypercalcemia and gastrointestinal issues, and their use should be carefully managed to minimize these risks. The most common side effects of phosphate supplements include digestive issues such as nausea, vomiting, diarrhea, and stomach cramps 1. Some patients may experience more serious reactions like allergic responses, difficulty breathing, or swelling of the face, lips, tongue, or throat. High doses of phosphate can lead to hyperphosphatemia, which may cause calcium deposits in soft tissues, kidney damage, and disruption of the body's calcium-phosphate balance 1. Patients with kidney disease are particularly vulnerable to these complications.
When taking phosphate supplements, it's essential to follow dosing instructions carefully and take them with plenty of water. Phosphate works in the body by helping maintain bone health, energy production, and acid-base balance, but excessive amounts can overwhelm the kidneys' ability to maintain proper mineral balance. The choice of phosphate binder should be determined by patient preference, compliance, comorbid illnesses, side effects, cost, and the ability to control serum phosphorus levels while maintaining the desired calcium-phosphorus product 1.
Key considerations for minimizing side effects include:
- Taking phosphate binders 10 to 15 minutes before, or during, meals to optimize their effectiveness 1
- Avoiding the use of aluminum-containing phosphate binders, except in cases where serum phosphorus levels are greater than 7.0 mg/dL, and only for short-term therapy 1
- Considering the use of non-calcium, non-magnesium, non-aluminum phosphate binders, such as sevelamer, as the therapy of choice 1
- Monitoring patients for signs of hypercalcemia, gastrointestinal side effects, and other potential complications 1.
From the FDA Drug Label
Administration of calcium acetate in excess of the appropriate daily dosage may result in hypercalcemia [see Warnings and Precautions (5.1)]. The main side effect related to phosphate of calcium acetate is hypercalcemia.
- Hypercalcemia can occur if the dosage of calcium acetate exceeds the recommended daily dosage.
- The phosphate binding effect of calcium acetate can lead to a decrease in serum phosphorus levels, but excessive dosage can cause an increase in serum calcium levels, resulting in hypercalcemia. 2
From the Research
Phosphate Side Effects
- High serum phosphate levels are linked to poor health outcomes and mortality in chronic kidney disease (CKD) patients 3
- Hyperphosphatemia can lead to cardiovascular diseases and bone abnormalities in CKD patients 4, 3
- Phosphate binders, such as lanthanum carbonate and sevelamer carbonate, are used to treat hyperphosphatemia in CKD patients 4, 5, 6
- Lanthanum carbonate has been shown to be effective in lowering serum phosphate concentrations and managing hyperphosphatemia 4, 5
- However, lanthanum carbonate can cause adverse effects such as nausea, alkaline gastric reflux, and gastrointestinal obstruction 5
- Sevelamer carbonate can also cause gastrointestinal symptoms, but to a lesser extent than lanthanum carbonate 6
- Other phosphate binders, such as calcium-based binders and aluminum-containing binders, have different safety profiles and off-target actions 6
Management of Phosphate Intake
- Careful dietary management to reduce high phosphate intake is recommended to slow the progression of CKD and prevent complications 7, 3
- Limiting dietary phosphate intake can be challenging due to the hidden presence of phosphate additives in processed foods and medications 7
- Mandatory labeling of phosphate content on packaged foods and drugs could enable better management of dietary phosphate intake 7