Sevelamer
💊 About Sevelamer
⚠️ Always
check the BNF here
for up-to-date UK prescribing details (formulation, dose ranges, cautions, interactions).
- 🧂 Sevelamer is a non-calcium, non-metal phosphate binder used to treat hyperphosphataemia in chronic kidney disease (CKD), especially in patients on dialysis (HD or PD).
- 🧠 Key aim: reduce phosphate load → protect bone and blood vessels (CKD-MBD).
🧬 Why Phosphate Matters in CKD (Pathophysiology)
- 🩺 In CKD, phosphate excretion falls → phosphate retention develops.
- 🧠 High phosphate stimulates FGF-23 and reduces calcitriol → lowers calcium absorption → drives secondary hyperparathyroidism.
- 🦴 This contributes to renal osteodystrophy (bone pain, fractures).
- 🫀 Chronic hyperphosphataemia accelerates vascular/valvular calcification → increased cardiovascular mortality.
⚙️ Mode of Action
- 🍽️ Sevelamer binds dietary phosphate in the gut lumen.
- 🚫 The bound phosphate is not absorbed → passed in stool → lowers serum phosphate.
- ✅ Because it contains no calcium, it helps avoid calcium loading and may reduce calcification risk compared with calcium-based binders in some patients.
🎯 Indications
- 🩸 Hyperphosphataemia in patients on haemodialysis or peritoneal dialysis.
- 🧪 Hyperphosphataemia in non-dialysis CKD where dietary measures are insufficient (e.g. serum phosphate > 1.78 mmol/L).
🚫 Contraindications & Cautions
- ⛔ Bowel obstruction.
- ⚠️ Use caution in severe GI motility disorders, dysphagia, prior major GI surgery, or recurrent constipation.
- 💧 PD patients: maintain vigilance for infective complications and abdominal symptoms.
🔁 Interactions (Practical Prescribing Tips)
- 💊 Can reduce ciprofloxacin absorption → avoid co-administration (separate dosing or choose alternative antibiotic where possible).
- ⏱️ General rule: separate sevelamer from susceptible drugs by at least 1–3 hours (check BNF for each drug).
- 🧠 If INR control becomes unstable in a warfarin patient who starts a binder, re-check adherence/timing and consider closer monitoring (interaction is usually timing/absorption-related rather than direct).
⚠️ Side Effects
- 🤢 GI: nausea, bloating, abdominal pain, constipation, diarrhoea, dyspepsia.
- 🧱 Rare but important: faecal impaction, ileus, bowel obstruction/perforation (red flags = severe pain, vomiting, no bowel movements).
- 🌡️ Other: headache, rash.
- 🧫 Peritoneal dialysis: possible association with increased risk of peritonitis in some cohorts (monitor symptoms; treat promptly).
💡 Dose & Administration (High-Yield)
- 🍽️ Take with meals (it must meet phosphate in the gut to work).
- Initial: 2.4–4.8 g daily in 3 divided doses with meals.
- Maintenance: often ~6 g daily in 3 divided doses, titrated to response.
- 🔁 Adjust every 2–4 weeks to reach local phosphate targets (guided by renal team).
✅ Clinical pearl: If phosphate remains high despite “being on binders”, the commonest causes are timing (not with meals), missed doses, and dietary phosphate load.
Ask specifically: “Do you take it with the first few mouthfuls?” 🍽️
🧪 Monitoring
- 🩸 Serum phosphate (trend is more useful than single readings).
- 🦴 Calcium, PTH, alkaline phosphatase (CKD-MBD picture).
- 🍽️ Diet review with renal dietitian (phosphate additives are a frequent hidden culprit).
📚 References
