What is the recommended dose of Sevelamer (sevelamer hydrochloride) for controlling hyperphosphatemia in patients with chronic kidney disease (CKD)?

Recommended Dosing of Sevelamer for Hyperphosphatemia in CKD

The recommended starting dose of sevelamer hydrochloride is 800 mg three times per day with meals (2.4 g/day total), with titration by one tablet per meal every two weeks to achieve target serum phosphorus levels. 1

Dosing Guidelines Based on CKD Stage

For CKD Patients on Dialysis (Stage 5):

• Starting dose: 800 mg three times daily with meals (2.4 g/day)
• Titration: Increase by one tablet per meal (800 mg) every 2 weeks
• Target serum phosphorus: 3.5-5.5 mg/dL 2
• Average effective dose: 4.9-6.5 g/day (range 0.8-13 g/day) based on clinical trials 1

For CKD Patients Not on Dialysis (Stages 3-4):

• Starting dose: Same as dialysis patients - 800 mg three times daily with meals
• Target serum phosphorus: 2.7-4.6 mg/dL 2
• Initiate when: Serum phosphorus >4.6 mg/dL despite dietary phosphorus restriction 2

Dose Titration Algorithm

1. Baseline measurement: Check serum phosphorus level
2. Initiate therapy: Start with 800 mg three times daily with meals
3. Follow-up monitoring: Check serum phosphorus after 2 weeks
4. Titration: Increase dose by one tablet per meal if target not achieved
5. Maximum dose: Based on clinical trials, doses up to 13 g/day have been used 1

Clinical Considerations

Administration Requirements

• Must be taken with meals to effectively bind dietary phosphate 3
• Cannot be taken as a dry powder; tablets must be swallowed whole 1
• Do not take simultaneously with ciprofloxacin or mycophenolate mofetil 1

Monitoring Parameters

• Serum phosphorus: Every 2-4 weeks during titration, then monthly
• Serum calcium: Monitor for hypercalcemia if switching from calcium-based binders
• Serum bicarbonate: Monitor for metabolic acidosis, especially when switching from sevelamer hydrochloride to carbonate formulation 4

Efficacy Considerations

• In clinical trials, sevelamer reduced serum phosphorus by approximately 2 mg/dL from baseline 1
• Average daily dose at the end of treatment in hemodialysis patients was 6.5 g/day (range 0.8-13 g) 1
• In peritoneal dialysis patients, average daily dose was 5.9 g/day (range 0.8-14.3 g) 1

Special Populations and Considerations

Patients with Hypercalcemia

Sevelamer is preferred over calcium-based phosphate binders in:

• Patients with serum calcium >10.2 mg/dL 2
• Patients with PTH <150 pg/mL 2
• Patients with vascular/soft tissue calcifications 2

Combination Therapy

• For patients who remain hyperphosphatemic (>5.5 mg/dL) despite maximum tolerated dose of either calcium-based or sevelamer, a combination of both types of binders is recommended 2

Common Pitfalls and Caveats

1. Pill burden: Sevelamer requires multiple tablets per day which can reduce adherence
2. GI side effects: Most common adverse reactions are gastrointestinal (dyspepsia, diarrhea, nausea, constipation) 1
3. Drug interactions: Separate administration time from ciprofloxacin and mycophenolate mofetil 1
4. Bowel obstruction: Rare but serious cases have been reported; use with caution in patients with swallowing disorders or severe GI motility disorders 1

By following this dosing algorithm and monitoring parameters, hyperphosphatemia in CKD patients can be effectively managed with sevelamer, potentially reducing the risk of vascular calcification and associated cardiovascular morbidity and mortality.