Fosrenol
Generic name: lanthanum carbonate · Brand names: Fosrenol
Class II recall · Ongoing
Failed stability specifications: Out of specification for hardness test
Posted October 24, 2025. Check lot numbers with your pharmacy before taking Fosrenol. View FDA recall notices.
Information sourced from FDA Structured Product Labeling, updated December 31, 2024.
What is it used for?
1 INDICATIONS AND USAGE FOSRENOL ® is a phosphate binder indicated to reduce serum phosphate in patients with end-stage renal disease (ESRD). Management of elevated serum phosphorus levels in patients with ESRD usually includes all of the following: reduction in dietary intake of phosphate, removal of phosphate by dialysis, and reduction of intestinal phosphate absorption with phosphate binders. FOSRENOL is a phosphate binder indicated to reduce serum phosphate in patients with end-stage renal disease (ESRD).
How to take it
Divide the total daily dose of FOSRENOL and take with or immediately after meals. The recommended initial total daily dose of FOSRENOL is 1,500 mg. Titrate the dose every 2 to 3 weeks until an acceptable serum phosphate level is reached. Monitor serum phosphate levels as needed during dose titration and on a regular basis thereafter.
FOSRENOL has the potential to bind other orally administered drugs; consider separating the administration of other oral medications . In clinical studies of patients with ESRD, FOSRENOL doses up to 4,500 mg were evaluated. Most patients required a total daily dose between 1,500 mg and 3,000 mg to reduce plasma phosphate levels to less than 6.0 mg/dL. Doses were generally titrated in increments of 750 mg/day. The recommended initial total daily dose of FOSRENOL is 1,500 mg in divided doses.
Titrate every 2 to 3 weeks based on serum phosphate level. Take FOSRENOL with or immediately after meals. FOSRENOL Chewable Tablets: Chew or crush tablet completely before swallowing. FOSRENOL Oral Powder: Sprinkle powder on a small quantity of applesauce or other similar food and consume immediately.
Consider powder formulation in patients with poor dentition or who have difficulty chewing tablets. Information for FOSRENOL Chewable Tablets Chew or crush FOSRENOL Chewable Tablets completely before swallowing. Do not swallow intact FOSRENOL Chewable Tablets. Information for FOSRENOL Oral Powder Sprinkle FOSRENOL Oral Powder on a small quantity of applesauce or other similar food and consume immediately.
Do not open until ready to use. Do not store FOSRENOL Oral Powder for future use once mixed with food. Because FOSRENOL Oral Powder is insoluble, do not attempt to dissolve in liquid for administration. Consider using the oral powder formulation in patients with poor dentition or who have difficulty chewing tablets.
Warnings
Serious cases of gastrointestinal obstruction, ileus, subileus, gastrointestinal perforation, and fecal impaction. Risks include altered gastrointestinal anatomy, hypomotility disorders, and concomitant medications. Advise patients to chew or crush the tablet completely. FOSRENOL has radio-opaque properties and, therefore, may give the appearance typical of an imaging agent during abdominal X-ray procedures.
Gastrointestinal Adverse Effects Serious
cases of gastrointestinal obstruction, ileus, subileus, gastrointestinal perforation, and fecal impaction have been reported in patients taking lanthanum, some requiring surgery or hospitalization. Consider discontinuing FOSRENOL in patients without another explanation for severe gastrointestinal symptoms. Risk factors for gastrointestinal obstruction and gastrointestinal perforation identified from post-marketing reports in patients taking FOSRENOL Chewable Tablets include abnormal gastrointestinal anatomy (e.g., diverticular disease, peritonitis, history of gastrointestinal surgery, gastrointestinal cancer, gastrointestinal ulceration), hypomotility disorders (e.g., constipation, ileus, subileus, diabetic gastroparesis), and the use of medications known to potentiate these effects.
Some cases were reported in patients with no history of gastrointestinal disease. Patients with acute peptic ulcer, ulcerative colitis, Crohn's disease, or bowel obstruction were not included in FOSRENOL clinical studies . Advise patients who are prescribed FOSRENOL Chewable Tablets to chew the tablet completely and not to swallow them whole. Serious gastrointestinal complications have been reported in association with unchewed or incompletely chewed tablets .
Diagnostic Tests
FOSRENOL has radio-opaque properties and therefore may give the appearance typical of an imaging agent during abdominal X-ray procedures. Postmarketing reports of product residue have been reported during endoscopic imaging.
Who should not take it
Contraindicated in patients with: - hypersensitivity to FOSRENOL or to any ingredient in the formulation. - bowel obstruction, including ileus and fecal impaction. Hypersensitivity to FOSRENOL or to any ingredient in the formulation. Bowel obstruction, ileus, and fecal impaction.
Pregnancy
Pregnancy Risk Summary Available
data from case reports with use of FOSRENOL in pregnant women are insufficient to identify a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. In animal reproduction studies, oral administration of lanthanum carbonate to pregnant rats and rabbits during organogenesis at doses 3 and 2.5 times, respectively, the maximum recommended human dose (MRHD), resulted in no adverse developmental effects. In rabbits, lanthanum carbonate doses 5 times the MRHD was associated with maternal toxicity and resulted in increased post-implantation loss, reduced fetal weights, and delayed fetal ossification . Deposition of lanthanum into developing bone, including growth plate, was observed in juvenile animals in long-term animal studies with lanthanum carbonate . Use a non-lanthanum containing phosphate binder in a pregnant woman.
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defect and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
Data Animal Data In pregnant rats, oral administration of lanthanum carbonate at doses as high as 2,000 mg/kg/day during organogenesis resulted in no evidence of harm to the fetus. The MRHD for FOSRENOL is 5,725 mg, representing a dose of 95.4 mg/kg, or 3,530 mg/m 2 for a 60-kg patient. The 2,000-mg/kg/day dose in the rat is equivalent to 12,000 mg/m 2 , 3 times the MRHD. In pregnant rabbits, oral administration of lanthanum carbonate at 1,500 mg/kg/day (18,000 mg/m 2 ; 5 times the daily MRHD) during organogenesis was associated with increased post-implantation loss, reduced fetal weights, and delayed fetal ossification.
No effects on the pregnant rabbits or fetuses were observed at 750 mg/kg/day (9,000 mg/m 2 ; 2.5 times the MRHD). In a pre- and postnatal development study in the rat, pregnant rats were dosed at up to 2,000 mg/kg/day (12,000 mg/m 2 /day; equivalent to 3 times the MRHD) from day 6 of pregnancy through 20 days postpartum (including lactation). At 2,000 mg/kg/day, no maternal toxicity was observed, nor were any changes seen with respect to gestational length or delivery; however, piloerection/pallor, delayed eye opening, decreased body weight, and delayed sexual development were observed in the offspring at 2,000 mg/kg/day.
At 200 and 600 mg/kg/day (equivalent to 0.3 and 1 time the MRHD, respectively), slight delays in sexual development (delayed vaginal opening) were observed in the female offspring .
Side effects
The following adverse reactions are discussed in greater detail in other sections of the labeling: Gastrointestinal Adverse Effects In controlled trials, the most common adverse reactions that were more frequent (≥5% difference vs. placebo) in FOSRENOL were nausea, vomiting, and abdominal pain. The following adverse reactions have been identified during post-approval use of FOSRENOL: constipation, dyspepsia, allergic skin reactions, and tooth injury while chewing the tablet. To report SUSPECTED ADVERSE REACTIONS, contact Takeda Pharmaceuticals U.S.A., Inc. at 1-877-TAKEDA-7 (1-877-825-3327) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
Clinical Trials Experience Because
clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Overall, the safety profile of FOSRENOL has been studied in over 5,200 subjects in completed clinical trials. The most common adverse reactions for FOSRENOL were gastrointestinal events, such as nausea, vomiting, and abdominal pain and they generally abated over time with continued dosing.
In double-blind, placebo-controlled studies where a total of 180 and 95 patients with ESRD were randomized to FOSRENOL chewable tablet and placebo, respectively, for 4 to 6 weeks of treatment, the most common reactions that were more frequent (≥5% difference) in the FOSRENOL group were nausea, vomiting, and abdominal pain (Table 1). Table 1. Adverse Reactions Expressed as the event rate for each term That Were More Common on FOSRENOL in Placebo-Controlled, Double-Blind Studies with Treatment Periods of 4 to 6 Weeks FOSRENOL % (N=180) Placebo % (N=95) Nausea 11 5 Vomiting 9 4 Abdominal pain 5 0 In an open-label, long-term 2-year extension study in 93 patients who had transitioned from other studies, resulting in a total of up to 6 years treatment, mean baseline values and changes in transaminases were similar to those observed in the earlier comparative studies, with little change during treatment.
The safety of FOSRENOL was studied in two long-term, open-label clinical trials, which included 1,215 patients treated with FOSRENOL and 944 with alternative therapy. Fourteen percent (14%) of patients treated with FOSRENOL discontinued treatment due to adverse events. Gastrointestinal adverse reactions, such as nausea, diarrhea, and vomiting were the most common types of event leading to discontinuation.
In pooled active comparator controlled clinical trials, hypocalcemia was noted with an incidence of approximately 5% in both lanthanum and active comparator groups. A nonclinical study and a phase 1 study have shown reduced absorption of calcium in the intestine with lanthanum carbonate treatment. In a crossover study in 72 healthy individuals comparing FOSRENOL Chewable Tablets to FOSRENOL Oral Powder, gastrointestinal adverse reactions such as nausea, diarrhea, and vomiting were more common for the oral powder formulation (18%) than for the chewable tablets (7%).
Postmarketing Experience The
following adverse reactions have been identified during post-approval use of FOSRENOL. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Cases of constipation, intestinal perforation, intestinal obstruction, ileus, subileus, dyspepsia, allergic skin reactions, hypophosphatemia, and tooth injury while chewing the tablet have been reported.
All information on this site is provided “as-is” for informational purposes only and is not a substitute for medical advice or treatment. You should consult with a medical professional if you have any questions about your health. Source: FDA Structured Product Labeling.