Sevelamer
Sevelamer
Generic Name
Sevelamer
Brand Names
Renagel®/Apselos®/Renvela®) is a non‑absorbable, calcium‑free phosphate‑binding polymer approved for treating hyperphosphatemia in patients with chronic kidney disease (CKD) or on dialysis.
Mechanism
- Non‑absorbed, polymeric resin that binds dietary phosphorus in the gastrointestinal tract forming insoluble complexes excreted in feces.
- Prevents absorption of both inorganic phosphate salts and phytate (plant‑derived phosphates).
- Calcium‑free binder: avoids excess calcium deposition, thereby reducing the risk of vascular calcification and hypercalcemia.
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Pharmacokinetics
- No systemic absorption; fraction < 0.1 % reaches bloodstream.
- Excreted unchanged in feces; no renal, hepatic, or significant metabolic pathway involvement.
- Not metabolized; drug‑drug interactions are mainly competitive for bowel lumen binding (e.g., with iron, calcium salts, or other phosphate binders).
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Indications
- Hyperphosphatemia due to CKD stages 3–5 (no dialysis required).
- Hyperphosphatemia in maintenance hemodialysis or peritoneal dialysis patients.
- Used in combination with dietary phosphate restriction and, when needed, other phosphate‑binding agents.
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Contraindications
| Category | Details |
| Contraindications |
• Intestinal obstruction or severe paralytic ileus. • Severe constipation or malabsorptive disorders. • Suspected bowel obstruction. |
| Warnings |
• Can reduce the absorption of fat‑soluble vitamins A, D, E, K – monitor levels in high‑risk patients. • May delay absorption of tiotropium, canagliflozin, calcitriol, and other drugs taken orally at the same time. • Potential to precipitate intestinal obstruction if administered in large volumes or with poor GI motility. |
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Dosing
| CKD Stage | Dialysis Regimen | Starting Dose | Titration |
| Non‑dialysis CKD 3‑5 | Not applicable | 1.5–3 g orally with each main meal (2–3 tablets/kg) | Increase by 0.5–1 g every 1–2 weeks until plasma phosphate < 5 mg/dL (1.3 mmol/L). |
| Maintenance hemodialysis | 3–4 h sessions | 1.0–1.5 g per meal | Adjust to maintain plasma phosphate within target range. |
| Peritoneal dialysis | Continuous | 1.5–2.0 g per meal | Similar titration; review weekly. |
• Take with meals to maximize binding of dietary phosphorus.
• For tablet formulations (Renagel® 1 g), one tablet ≈ 1 g, but dosing often requires multiple tablets (fractional tablet strategy).
• If using the liquid formulation (Renvela® 500 mL), 150 mL ≈ 1 g.
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Adverse Effects
Common (≥ 10 %)
• Nausea, bloating, abdominal discomfort
• Diarrhea, constipation
• Early satiety, mild dysphagia
• Pruritus (due to drug–food interaction)
Serious (≤ 1 %)
• Intestinal obstruction or perforation (especially in patients with altered GI motility)
• Bowel ischemia (rare, usually with concurrent conditions)
• Severe hypophosphatemia (if over‑treated)
• Allergic reactions (rare)
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Monitoring
| Parameter | Frequency | Rationale |
| Serum phosphorus | Every 2–4 weeks (or sooner if dose changes) | Evaluate efficacy, avoid overshoot |
| Serum calcium and PTH | Monthly | Detect hypocalcemia, hyperparathyroidism progression |
| Vit. D, A, E, K levels | Every 3–6 months in high‑risk | Prevent deficiencies |
| GI symptoms | At each visit | Identify early intolerance or obstruction |
| Iron studies | If iron supplementation is used | Conserve iron stores; mitigate GI bleeding |
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Clinical Pearls
1. “Calcium‑free by design” – Sevelamer reduces the risk of vascular calcification most effectively when paired with a limiting calcium intake strategy.
2. Dual benefit in CKD – Beyond phosphate control, sevelamer lowers LDL cholesterol by binding bile acids; consider it in patients with hyperlipidemia and CKD.
3. Timing matters – Take sevelamer 1–2 h before/after oral iron salts or calcium acetate to avoid neutralization of the phosphate‑binding effect.
4. Titration should be frequent – Because the GI tract can vary day‑to‑day, adjust doses every 1–2 weeks in the first month for optimal serum phosphate control.
5. Watch for “drug‑binding” – Sevelamer can bind digoxin and other lipophilic drugs; if patients require such agents, consider a 3 h separation window.
6. Use fractional tablets – Rather than adjusting total daily dose, split tablets among meals; this simplifies patient adherence.
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• Sevelamer remains a cornerstone therapy for hyperphosphatemia in CKD, offering a combination of efficacy, minimized systemic exposure, and additional cardiovascular benefits when correctly dosed and monitored.