What is the emergent management of severe hyperphosphatemia?

From the Guidelines

The emergent management of severe hyperphosphatemia, such as a level of 6.8 and rising, should prioritize reducing serum phosphate levels quickly through interventions like discontinuing phosphate-containing medications, limiting dietary phosphate intake, and administering phosphate binders, with a focus on avoiding hypercalcemia and potential harm from calcium-based binders, as suggested by recent studies 1.

Key Interventions

• Discontinue all phosphate-containing medications and limit dietary phosphate intake to minimize phosphate absorption.
• Administer phosphate binders, considering the potential benefits and risks of different types, such as sevelamer or lanthanum carbonate, which may be preferred over calcium-based binders due to the risk of hypercalcemia and vascular calcification 1.
• Initiate intravenous hydration with normal saline to enhance phosphate excretion, monitoring carefully in patients with heart or kidney failure.
• For patients with functioning kidneys, consider loop diuretics like furosemide to increase phosphate excretion.

Considerations for Severe Cases

• In severe cases or when kidney function is impaired, urgent hemodialysis or continuous renal replacement therapy may be necessary, particularly when phosphate levels exceed 10 mg/dL or when severe symptoms are present.
• Frequent monitoring of serum phosphate, calcium, and kidney function is essential during treatment to adjust interventions as needed and prevent complications.

Prioritizing Patient Safety

• The management strategy should prioritize avoiding hypercalcemia, as higher calcium concentrations have been linked to increased mortality and nonfatal cardiovascular events in adults with CKD 1.
• The choice of phosphate binder should consider the potential for calcium-free agents to reduce the risk of vascular calcification and other complications associated with calcium-based binders 1.

From the FDA Drug Label

The ability of sevelamer hydrochloride to lower serum phosphorus in CKD patients on dialysis was demonstrated in six clinical trials: one double-blind placebo-controlled 2-week study (sevelamer hydrochloride N=24); two open-label uncontrolled 8-week studies (sevelamer hydrochloride N=220) and three active-controlled open-label studies with treatment durations of 8 to 52 weeks (sevelamer hydrochloride N=256). Eighty-four CKD patients on hemodialysis who were hyperphosphatemic (serum phosphorus >6 mg/dL) following a two-week phosphate binder washout period received sevelamer hydrochloride and active-control for eight weeks each in random order. Both treatments significantly decreased mean serum phosphorus by about 2 mg/dL

For a patient with severe hyperphosphatemia of 6.8 mg/dL and rising, the emergent management may include the use of a phosphate binder such as sevelamer hydrochloride. The dose of sevelamer hydrochloride can be titrated to control serum phosphorus levels, with an average daily dose ranging from 0.8 to 13 g. It is essential to monitor serum phosphorus levels closely and adjust the dose as needed to achieve the desired level of phosphorus control 2.

• Key points to consider in the emergent management of severe hyperphosphatemia include:
  • Initiation of phosphate binder therapy, such as sevelamer hydrochloride
  • Close monitoring of serum phosphorus levels
  • Titration of the phosphate binder dose to achieve the desired level of phosphorus control
  • Consideration of other treatment options, such as dialysis, in severe cases of hyperphosphatemia.

From the Research

Emergent Management of Severe Hyperphosphatemia

• The emergent management of severe hyperphosphatemia, such as a level of 6.8 and rising, is crucial to prevent further complications 3.
• Hyperphosphatemia can be induced by a massive acute phosphate load, primary increase in renal phosphate reabsorption, or impaired renal phosphate excretion due to acute or chronic renal insufficiency 3.
• Treatment options for hyperphosphatemia include diminishing intestinal phosphate absorption by a low phosphate diet and phosphate binders 3.

Phosphate Binders

• Phosphate binders are a crucial part of managing hyperphosphatemia, and various types are available, including calcium-based, non-calcium-based, and aluminum-containing agents 3, 4, 5.
• Calcium-based phosphate binders are effective but may increase the risk of calcium overload and hypercalcemia 4, 5.
• Non-calcium-based phosphate binders, such as sevelamer, lanthanum carbonate, and magnesium salts, are also effective and may have a more favorable safety profile 3, 4, 5.

Patient Empowerment and Phosphate Control

• Patient empowerment in managing hyperphosphatemia is crucial, and education programs can help patients self-adjust their phosphate binder dose according to their dietary phosphorus intake 6.
• Phosphate control is a significant challenge in end-stage renal disease, and barriers to achieving optimal phosphate levels include inadequate phosphate binder dosing and non-adherence to treatment 7.

Clinical Considerations

• The choice of phosphate binder should be individualized, considering the clinical context, costs, and individual tolerability, as well as the concomitant effects on other parameters of mineral metabolism 3.
• Close monitoring of serum phosphorus levels and adjustment of phosphate binder dose as needed is essential to achieve optimal phosphate control 3, 4, 5.