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Lanthanum (Monograph)

Brand name: Fosrenol
Drug class: Phosphate-removing Agents
VA class: GU900
Chemical name: Dilanthanum tricarbonate hydrate
Molecular formula: La2(CO3)3 • H2O
CAS number: 54451-24-0

Medically reviewed by on Apr 21, 2023. Written by ASHP.


Phosphate binder used to reduce the intestinal absorption of phosphates.

Uses for Lanthanum


Reduction of serum phosphorus in patients with end-stage renal disease (ESRD). Reductions in serum phosphorus concentrations are similar to those achieved with alternative phosphate binders (e.g., calcium salts, sevelamer).

Risk of hypercalcemia apparently is less than with calcium (e.g., calcium carbonate) salts.

Lanthanum Dosage and Administration


Oral Administration

Administer orally in divided doses with or immediately after meals (in order to bind dietary phosphates efficiently).

Chew tablets completely before swallowing; do not swallow intact tablets.


Available as lanthanum carbonate; dosage expressed in terms of lanthanum.



Initially, 750 mg–1.5 g daily.

Adjust dosage at 2- to 3-week intervals until serum phosphorus concentration is acceptable; generally titrated in increments of 750 mg daily in clinical studies.

Dosage of 1.5–3 g daily usually is required to reduce serum phosphorus concentrations to <6 mg/dL; dosages up to 3.75 g daily have been studied.

Monitor serum phosphorus concentrations as needed during titration and regularly thereafter.

Cautions for Lanthanum


  • No known contraindications.


General Precautions

GI Disease

Safety and efficacy not established in active peptic ulcer disease, ulcerative colitis, Crohn’s disease, or bowel obstruction; use with caution in patients with these disorders.

Radiographic Examinations

Abdominal radiographs performed in patients taking lanthanum may have the typical radiopaque appearance of a radiograph performed using an imaging agent.

Chronic Use

No differences in fracture or mortality rates were observed between patients receiving lanthanum and those receiving alternative therapy for up to 3 years in clinical studies; however, data are insufficient to conclude lanthanum has no effect on fracture or mortality rates beyond 3 years of use.

Specific Populations


Category C.


Not known whether lanthanum is distributed into milk. Caution if used in nursing women.

Pediatric Use

Safety and efficacy not established in children <18 years of age.

Deposited in developing bone (including the growth plate) of animals in long-term studies; although growth abnormalities in animals were not observed, the consequences of deposition in developing bone of pediatric patients are unknown.

Geriatric Use

No substantial differences in safety and efficacy relative to younger adults.

Common Adverse Effects

Nausea, vomiting, dialysis graft occlusion, abdominal pain.

Interactions for Lanthanum

Not a substrate for CYP isoenzymes. Does not inhibit CYP isoenzymes 1A2, 2C9/10, 2C19, 2D6, or 3A4/5.

Drugs Affecting or Metabolized by Hepatic Microsomal Enzymes

Pharmacokinetic interaction unlikely.

Drugs Known to Interact with Antacids

Possible formation of insoluble complexes; do not administer such drugs within 2 hours of lanthanum dose.

Specific Drugs



Citrate salts

Lanthanum absorption not altered


No formation of insoluble complexes in vitro; digoxin absorption not altered


No formation of insoluble complexes in vitro


No formation of insoluble complexes in vitro


No formation of insoluble complexes in vitro; metoprolol absorption not altered


No formation of insoluble complexes in vitro


No formation of insoluble complexes in vitro; warfarin absorption not altered

Lanthanum Pharmacokinetics


Information regarding the mass balance of lanthanum in humans after oral administration is not available.


Minimally absorbed from the GI tract; bioavailability <0.002%.


Minimal effect on systemic lanthanum concentrations.

Plasma Concentrations

Mean plasma concentrations of the drug remain low (≤1.1 ng/mL) for up to 2 years of use. Plasma concentrations increase minimally with increasing dosages in the recommended range.



Distributed into bone; bone lanthanum concentrations increase over time (e.g., 4.5 years of administration).

Does not appear to cross the blood-brain barrier in animals.

Plasma Protein Binding




Not metabolized.

Elimination Route

In animals, excreted principally in the feces (94–99%), mainly as unabsorbed drug; systemically absorbed lanthanum is eliminated in the feces, principally via biliary excretion.

Minimally excreted in urine in healthy individuals (renal clearance of IV lanthanum chloride [not commercially available in the US] is <2% of total plasma clearance).


Plasma: 53 hours.

Bone: 2–3.6 years.

Special Populations

In lanthanum-treated patients with ESRD, no quantifiable amounts were present in the dialysate.




Chewable Tablets

25°C (may be exposed to 15–30°C). Protect from moisture.


  • Dissociates in the acidic environment of the upper GI tract to release trivalent lanthanum ions, which bind dietary phosphate released during digestion, thereby forming highly insoluble lanthanum phosphate complexes that are excreted fecally.

  • Lanthanum ions have a high affinity for phosphate; the drug binds about 97% of available phosphates in vitro at pH 3–5 (corresponding to that of gastric fluid) when in twofold molar excess to phosphates.

  • Reduces phosphate absorption, serum phosphorus concentrations, and serum calcium times phosphorus product (Ca × P).

Advice to Patients

  • Importance of adhering to instructions about diet.

  • Importance of taking lanthanum with or immediately after meals.

  • Importance of chewing tablets completely before swallowing, and not swallowing intact tablets.

  • Importance of women informing their clinician if they are or plan to become pregnant or plan to breast-feed.

  • Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs, as well as any concomitant illnesses.

  • Importance of informing patients of other important precautionary information. (See Cautions.)


Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

Lanthanum Carbonate


Dosage Forms


Brand Names



Tablets, chewable

250 mg (of lanthanum)



500 mg (of lanthanum)



750 mg (of lanthanum)



1 g (of lanthanum)



AHFS DI Essentials™. © Copyright 2023, Selected Revisions May 1, 2006. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.

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