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Phosphate Binder (Lanthanum-Based)

Lanthanum Carbonate 750mg–3g/day (Fosrenol)

Brand names: Fosrenol

Adult dose

Dose: 750mg per meal initially (2250mg/day); titrate in increments of 750mg every 2–3 weeks based on serum phosphate. Usual maintenance: 1500–3000mg/day in divided doses.
Route: Oral (chewable tablet — must be chewed, not swallowed whole)
Frequency: Three times daily with or immediately after meals
Max: 3750mg/day
Titrate to target serum phosphate <1.78 mmol/L (dialysis patients). Chewable tablets — partial chewing then swallowing is acceptable. Available as 500mg, 750mg, 1000mg chewable tablets. Powder for oral suspension also available.

Paediatric dose

Route: N/A
Frequency: N/A
Max: Not licensed in children — insufficient safety data
Not licensed for use in patients <18 years.

Dose adjustments

Renal

No dose adjustment required — not systemically absorbed; designed specifically for dialysis/CKD patients

Hepatic

No dose adjustment required — not hepatically metabolised

Clinical pearls

  • Non-calcium, non-aluminium phosphate binder — avoids hypercalcaemia (unlike calcium carbonate/acetate) and aluminium toxicity (unlike aluminium hydroxide)
  • Must be chewed with or immediately after meals — binding dietary phosphate in upper GI tract is the mechanism; swallowing whole significantly reduces efficacy
  • Lanthanum has low systemic absorption (<0.001%) — bone accumulation reported in long-term animal studies but not confirmed clinically significant in humans over 10+ years of use
  • KDIGO CKD-MBD 2017: choice of phosphate binder should be individualised — lanthanum carbonate is preferred over calcium-based binders when hypercalcaemia is present
  • Patient counselling essential — chewable tablets are unpalatable; compliance is a common issue; powder formulation available as alternative

Contraindications

  • Hypophosphataemia
  • Bowel obstruction or ileus
  • Hypersensitivity to lanthanum carbonate

Side effects

  • Nausea and vomiting (especially initial titration period)
  • Diarrhoea
  • Constipation
  • Abdominal pain
  • Headache
  • GI obstruction (rare — chew thoroughly)

Interactions

  • Fluoroquinolones (ciprofloxacin, levofloxacin) — lanthanum reduces absorption; take 2h before lanthanum
  • Levothyroxine — reduced absorption; take 2h apart
  • Other drugs bound in GI tract — separate administration by 2h where clinically important

Monitoring

  • Serum phosphate (every 1–3 months)
  • Serum calcium (to ensure no hypocalcaemia)
  • GI symptoms (nausea, bowel habit)

Reference: BNFc; BNF; KDIGO CKD-MBD Guidelines 2017; Fosrenol SPC; NICE TA117. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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