What is the treatment for hyperphosphatemia in patients with chronic kidney disease using Renvela (sevelamer)?

Treatment of Hyperphosphatemia in CKD Using Sevelamer (Renvela)

Sevelamer is the preferred non-calcium, non-aluminum phosphate binder for treating hyperphosphatemia in CKD patients when dietary phosphorus restriction is insufficient to maintain normal phosphorus levels or when calcium-based binders are contraindicated due to hypercalcemia. 1, 2

First-Line Approach

• Begin with dietary phosphate restriction, limiting intake to 80-100% of the daily recommended intake, considering phosphate sources (animal vs. vegetable, processed foods with additives) 1
• Monitor serum phosphorus levels regularly, as dietary restriction alone is often insufficient to maintain normophosphatemia 1
• Initiate phosphate-lowering treatment only for progressive or persistent hyperphosphatemia, not for prevention in normophosphatemic patients 1

Sevelamer Treatment Algorithm

Indications for Sevelamer:

• Primary indication: Control of serum phosphorus in CKD patients on dialysis 2
• Secondary indications:
  • Hypercalcemia while on calcium-based phosphate binders 1
  • Excessive total calcium intake (>2000 mg/day from diet plus binders) 1
  • Progression of vascular calcification on calcium-based binders 1

Dosing and Administration:

• Start with 800-1600 mg three times daily with meals 2
• Titrate dose every 2-3 weeks based on serum phosphorus levels 2
• Target serum phosphorus within normal laboratory range 1
• Average effective dose ranges from 4.9-6.5 g/day (range 0.8-14.3 g/day) 2
• Available as sevelamer hydrochloride (Renagel) or sevelamer carbonate (Renvela) 3, 4

Formulation Selection:

• Sevelamer carbonate is preferred in patients at risk of metabolic acidosis as it has buffering capacity 3, 4
• Sevelamer carbonate is available as tablets or powder for oral suspension, providing options for patients with swallowing difficulties 4, 5

Monitoring and Follow-up

• Monitor serum phosphorus, calcium, calcium-phosphorus product, and PTH levels regularly 1
• Assess for metabolic acidosis, particularly with sevelamer hydrochloride 1
• Monitor lipid profile, as sevelamer has beneficial effects on LDL cholesterol levels 1, 4
• Evaluate for gastrointestinal side effects, the most common adverse events 3, 4

Comparative Efficacy

• Sevelamer is equally effective as calcium-based binders in controlling serum phosphorus levels 1, 6
• Sevelamer causes fewer episodes of hypercalcemia compared to calcium-based binders 1, 6
• Sevelamer attenuates progression of arterial calcification compared to calcium-based binders 1, 4
• Sevelamer may provide mortality benefit in incident dialysis patients 1, 4

Special Considerations

• Pill burden is a major challenge affecting adherence; individualize therapy considering this limitation 1
• For patients unable to swallow tablets, sevelamer carbonate powder formulation is available 4, 5
• For patients with enteral feeding tubes, crushed sevelamer tablets can be administered with proper preparation 5
• Consider intensified dialysis protocols if phosphate control cannot be achieved with binders alone 1

Potential Pitfalls and Caveats

• Avoid initiating phosphate binders in normophosphatemic CKD patients as this may not provide benefit and could potentially increase vascular calcification 1
• Be aware that sevelamer may cause metabolic acidosis, particularly the hydrochloride formulation 1, 3
• Recognize that the high pill burden may significantly impact patient adherence and quality of life 1
• Consider that sevelamer has significantly higher acquisition costs than calcium-based binders, though cost-effectiveness analyses have shown mixed results 3, 4