Phosphate binder
Pregnancy: 'Fosrenol is not recommended for use during pregnancy.' There are no adequate data in pregnant women; one rat study showed reproductive foetotoxicity and reduced pup weights at high doses and the potential risk for humans is unknown. Breast-feeding: it is unknown whether lanthanum is excreted in human breast milk — caution should be used in deciding whether to continue/discontinue breastfeeding or therapy (§4.6).
Lanthanum carbonate
Brand names: Fosrenol
Lanthanum carbonate is a non-aluminium, non-calcium phosphate binder used to control hyperphosphataemia in patients with chronic kidney disease, particularly those on dialysis.
Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.
Adult dose
Dose: Titrate to serum phosphate: 'Control of serum phosphate level has been demonstrated at doses starting from 750 mg per day.' 'Patients who respond to lanthanum therapy, usually achieve acceptable serum phosphate levels at doses of 1500-3000 mg lanthanum per day.'
Route: Oral. 'The tablets must be chewed completely and not swallowed whole. To aid with chewing the tablets may be crushed.' Where the oral powder is available it can replace chewable tablets in patients who have difficulty chewing the tablets
Frequency: Taken with or immediately after food, with the total daily dose divided between meals
Max: 'The maximum dose studied in clinical trials, in a limited number of patients, is 3750mg' (per day)
SOURCE: eMC UK SPC, productName 'Fosrenol 1000mg chewable tablets', §4.2 (https://www.medicines.org.uk/emc/product/7494/smpc). The §4.2 heading is 'Adults, including elderly (> 65 years)' — no separate elderly dose is given. TITRATION: 'Serum phosphate levels should be monitored and the dose of Fosrenol titrated every 2 to 3 weeks until an acceptable serum phosphate level is reached, with regular monitoring thereafter.' The SPC does not state a fixed starting dose beyond the 750 mg/day figure above — the clinician should confirm the local starting dose. DIET: 'Patients should adhere to recommended diets in order to control phosphate and fluid intake.' Fosrenol is a chewable tablet, avoiding the need to take additional fluid. HEPATIC IMPAIRMENT: 'Due to its mechanism of action and the lack of liver metabolism doses in hepatic impairment should not be modified, but patients should be monitored carefully.' SAFETY (§4.4): tablets must be chewed completely and not swallowed whole to reduce the risk of serious adverse gastrointestinal complications; cases of gastrointestinal obstruction, ileus, subileus and gastrointestinal perforation have been reported, some requiring surgery or hospitalisation, and use in patients predisposed to these (altered GI anatomy, hypomotility disorders such as constipation or diabetic gastroparesis) should only follow careful consideration; withdrawal is recommended in patients who develop severe constipation or other severe gastrointestinal signs and symptoms. Lanthanum deposition in gastroduodenal mucosa has been reported, mainly after long-term use. 'Patients with renal insufficiency may develop hypocalcaemia. Fosrenol does not contain calcium. Serum calcium levels should therefore be monitored at regular time intervals for this patient population and appropriate supplements given.' §4.4 and §4.8 text was truncated at the source-fetch limit. CROSS-CHECK ONLY (US label in the same bundle, Exelan Pharmaceuticals, 2024-08-01): 'The recommended initial total daily dose of lanthanum carbonate chewable tablets is 1,500 mg' in divided doses, titrated every 2 to 3 weeks, generally in increments of 750 mg/day, with doses up to 4,500 mg evaluated in ESRD studies — US figures are NOT carried into the dose field above, which is the UK SPC wording.
Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.
Contraindications
- Hypersensitivity to the active substance or to any of the excipients
- Hypophosphataemia
- Bowel obstruction (in subjects with ongoing bowel obstruction, lanthanum treatment is contraindicated)
Side effects
- Very common: abdominal pain, diarrhoea, nausea, vomiting (gastrointestinal reactions are minimised by taking with food and generally abate with time)
- Very common: headache. Common: constipation, dyspepsia, flatulence
- Common: hypocalcaemia. Uncommon: hypercalcaemia, hyperphosphataemia, hypophosphataemia, hyperparathyroidism, hyperglycaemia
- Uncommon: ileus, subileus, intestinal obstruction, oesophagitis, stomatitis, dry mouth; rare: intestinal perforation
- Post-marketing: allergic skin reactions including skin rashes, urticaria and pruritus (very common in clinical trials, in both Fosrenol and comparator groups); uncommon: dizziness, taste alteration, alopecia, arthralgia, myalgia, raised hepatic transaminases/GGT/alkaline phosphatase; transient QT changes have been observed but were not associated with an increase in cardiac adverse events
Interactions
- NOTE ON PROVENANCE: the eMC §4.5 section was not included in the fetched bundle — the entries below are taken from the US label in the same bundle and must be verified against the UK SPC §4.5
- Compounds that bind to cationic antacids (aluminium-, magnesium- or calcium-based) — do not administer such compounds within 2 hours of dosing with lanthanum carbonate; classes affected include antibiotics (quinolones, ampicillin, tetracyclines), thyroid hormones, ACE inhibitors, statin lipid regulators and anti-malarials
- Oral quinolone antibiotics — must be taken at least 1 hour before or 4 hours after lanthanum carbonate
- Thyroid hormone replacement therapy — do not take within 2 hours of dosing with lanthanum carbonate; monitoring of TSH levels is recommended in patients receiving both
- Other oral medicines where reduced bioavailability would have a clinically significant effect on safety or efficacy — consider separating the timing of administration of the two drugs
Clinical monograph
How it works
Lanthanum ions bind dietary phosphate in the gut to form insoluble lanthanum phosphate, reducing phosphate absorption and lowering serum phosphate.
Prescribing in practice
- Tablets must be chewed thoroughly and taken with or immediately after food to bind dietary phosphate effectively and reduce the risk of gastrointestinal complications.
- Gastrointestinal effects are common, and cases of bowel obstruction and gastrointestinal injury have been reported, especially in those at risk.
- It is not recommended in acute peptic ulcer, bowel obstruction or ileus.
Monitoring
Monitor serum phosphate regularly and titrate the dose to maintain it within the target range.
Counselling the patient
- Chew the tablets fully and take them with or just after meals.
- Report persistent abdominal pain, vomiting or constipation.
- Do not take it on an empty stomach, as this reduces its effect.
Evidence & guidelines
NICE guidance includes non-calcium-based phosphate binders such as lanthanum for managing hyperphosphataemia in chronic kidney disease.
Reference: NICE NG203; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).
Related
Curated clinical cross-links plus same-class fallbacks.