How to reduce hyperphosphatemia and hyperkalemia?

Management of Hyperphosphatemia and Hyperkalemia

For patients with hyperphosphatemia and hyperkalemia, potassium binders (patiromer or sodium zirconium cyclosilicate) are recommended as first-line therapy, along with dietary modifications and loop diuretics when appropriate. 1

Assessment of Severity

Hyperkalemia Classification:

• Mild: >5.0 to <5.5 mEq/L
• Moderate: 5.5 to 6.0 mEq/L
• Severe: >6.0 mEq/L 2

Hyperphosphatemia:

• Typically occurs when glomerular filtration rate falls below 30 ml/min/1.73 m² 3

Management Algorithm

1. Acute Management of Severe Hyperkalemia (>6.0 mEq/L)

• Calcium gluconate: 10% solution, 15-30 mL IV (onset: 1-3 minutes)
• Insulin with glucose: 10 units regular insulin IV with 50 mL of 25% dextrose (onset: 15-30 minutes)
• Inhaled beta-agonists: 10-20 mg nebulized over 15 minutes (onset: 15-30 minutes)
• Sodium bicarbonate: 50 mEq IV if acidotic (onset: 15-30 minutes)
• Discontinue or reduce RAASi therapy 1, 2

2. Chronic Management of Hyperkalemia (5.0-6.0 mEq/L)

Pharmacological Interventions:

• Potassium binders:

  • Patiromer (Veltassa): Shown to reduce both serum potassium and phosphate levels 4, 5
  • Sodium zirconium cyclosilicate (Lokelma): Effective for normalizing potassium levels 1
  • Sodium polystyrene sulfonate: 15-60g daily in divided doses (not for emergency treatment) 6

• Loop diuretics: Enhance potassium elimination if renal function permits 2

Medication Adjustments:

• Review and adjust medications that contribute to hyperkalemia:

  • RAASi (ACE inhibitors, ARBs, MRAs)
  • Potassium-sparing diuretics
  • NSAIDs
  • Beta-blockers
  • Calcineurin inhibitors 2

• For patients on RAASi with K+ levels >5.0-<6.5 mmol/L: Consider using potassium-lowering agents while maintaining RAASi therapy 2

• For patients with K+ levels >6.5 mmol/L: Discontinue or reduce RAASi therapy and initiate potassium-lowering agents 1

3. Management of Hyperphosphatemia

• Phosphate binders: Consider using patiromer which has dual action in reducing both potassium and phosphate levels 4, 5
• Loop diuretics: Enhance phosphate elimination if renal function permits 2

4. Dietary Modifications

• Potassium restriction:

  • Avoid high-potassium foods (bananas, oranges, potatoes, tomatoes)
  • Avoid salt substitutes (often contain potassium chloride) 1, 2

• Phosphate restriction:

  • Limit foods high in phosphorus (dairy products, processed foods, cola beverages)
  • Avoid foods with phosphate additives 7

• Moderate sodium restriction: To help manage fluid balance 2

Monitoring Protocol

• Check potassium and phosphate levels within 1 week of treatment initiation
• More frequent monitoring (every 1-2 weeks initially) for patients with CKD, heart failure, or diabetes
• Monitor for rebound hyperkalemia 2-4 hours after treatments that shift potassium intracellularly
• Monitor serum calcium and magnesium levels when using patiromer 2, 4

Important Considerations

• Patiromer has shown efficacy in reducing both serum potassium and phosphate levels, making it particularly valuable for patients with both conditions 4, 5
• Avoid relying solely on ECG changes to guide treatment decisions, as severe hyperkalemia can exist without typical ECG findings 2
• Avoid concomitant use of sodium polystyrene sulfonate with sorbitol due to risk of intestinal necrosis 6
• Take other orally administered drugs at least 3 hours before or 3 hours after sodium polystyrene sulfonate 6

Common Pitfalls to Avoid

• Permanent discontinuation of beneficial RAASi medications; aim to reintroduce at lower doses when possible
• Overlooking pseudo-hyperkalemia due to hemolysis during blood collection
• Neglecting to monitor for fluid overload in patients sensitive to sodium intake when using sodium-containing potassium binders
• Failing to recognize that dietary restrictions may impact quality of life and nutritional adequacy 2, 7