Phosphate Binder (Non-Calcium-Based) 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 calcium-free, aluminium-free phosphate binder used to control hyperphosphataemia in chronic kidney disease, particularly in dialysis patients.

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.' Some sections of the product information we used were incomplete — check the full SPC. 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 independently re-sourced from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — clinician-reviewed. 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

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
This interaction list may be incomplete — check the full SPC. Some of this information is from US labelling, which may differ from the UK SPC — check the full SPC.

Clinical monograph

How it works

In the gastrointestinal tract lanthanum binds dietary phosphate to form insoluble, poorly absorbed lanthanum phosphate, reducing phosphate absorption.

Prescribing in practice

Tablets must be chewed thoroughly and taken with or immediately after food to bind phosphate effectively and reduce the risk of gastrointestinal obstruction.
Gastrointestinal effects, and rarely bowel obstruction, perforation or ileus, can occur, so use caution in patients with gut motility disorders.
Separate administration from other oral medicines whose absorption may be impaired by binders.

Monitoring

Monitor serum phosphate, and calcium, to guide dose titration to target while avoiding over-suppression.

Counselling the patient

Always chew the tablets fully and take them with food, never on an empty stomach.
Report persistent constipation, severe abdominal pain or vomiting.
Take other tablets at a different time from your phosphate binder as advised.

Evidence & guidelines

Renal mineral and bone guidance supports phosphate binders such as lanthanum carbonate for managing hyperphosphataemia in CKD.

Reference: KDIGO CKD-MBD Clinical Practice Guideline Update 2017; Hutchison et al. NDT 2005 (lanthanum phase III); MHRA SPC Fosrenol; 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).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways