Fosrenol Information
Fosrenol () 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 end stage renal disease patients 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 () Dosage And Administration
In clinical studies of ESRD patients, Fosrenol () doses up to 4500 mg were evaluated. Most patients required a total daily dose between 1500 mg and 3000 mg to reduce plasma phosphate levels to less than 6.0 mg/dL. Doses were generally titrated in increments of 750 mg/day.
Consider potential drug interactions when prescribing Fosrenol () [].
Fosrenol () Dosage Forms And Strengths
Chewable Tablets: 500 mg, 750 mg, and 1000 mg.
Fosrenol () Contraindications
Bowel obstruction, ileus, and fecal impaction.
Fosrenol () Warnings And Precautions
There have been reports of serious cases of gastrointestinal obstruction, ileus, and fecal impaction reported in association with lanthanum, some requiring surgery or hospitalization.
Risk factors for gastrointestinal obstruction identified from post-marketing reports include alteration in gastrointestinal anatomy (e.g., history of gastrointestinal surgery, colon cancer), hypomotility disorders (e.g., constipation, ileus, diabetes) and concomitant medications (e.g., calcium channel blockers). Some cases were reported in patients with no history of gastrointestinal disease.
Advise patients to chew the tablet completely to reduce the risk of serious adverse gastrointestinal events such as those described above.
Patients with acute peptic ulcer, ulcerative colitis, Crohn's disease or bowel obstruction were not included in Fosrenol () clinical studies [].
Fosrenol () Adverse Reactions
Overall, the safety profile of Fosrenol () has been studied in over 5200 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.
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in 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.
In double-blind, placebo-controlled studies where a total of 180 and 95 ESRD patients were randomized to Fosrenol () and placebo, respectively, for 4-6 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).
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-labeled clinical trials, which included 1215 patients treated with Fosrenol () and 944 with alternative therapy. Fourteen percent (14%) of Fosrenol () treated patients 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.
Fosrenol () Drug Interactions
Lanthanum in Fosrenol () has the potential to bind to drugs with anionic (e.g., carboxyl, carbonyl, and hydroxyl) groups. Fosrenol () may decrease the bioavailability of tetracyclines or fluoroquinolones via this mechanism.
There are no empirical data on avoiding drug interactions between Fosrenol () and most concomitant drugs. When administering an oral medication where a reduction in the bioavailability of that medication would have a clinically significant effect on its safety or efficacy, administer the drug at least one hour before or three hours after Fosrenol () . Monitor blood levels of the concomitant drugs that have a narrow therapeutic range.
Fosrenol () Use In Specific Populations
Pregnancy Category C. No adequate and well-controlled studies have been conducted in pregnant women. The effect of Fosrenol () on the absorption of vitamins and other nutrients has not been studied in pregnant women. Fosrenol () is not recommended for use during pregnancy.
Studies in pregnant rabbits showed that oral administration of lanthanum carbonate at 1500 mg/kg/day (5 times the maximum recommended daily human dose (MRHD) of 5725 mg, on a mg/m basis, assuming a 60 kg patient) was associated with increased post-implantation loss, reduced fetal weights, and delayed fetal ossification [].
Fosrenol () Overdosage
The symptoms associated with overdose are adverse reactions such as headache, nausea and vomiting. In clinical trials in healthy adults, GI symptoms were reported with daily doses up to 6000 mg/day of lanthanum carbonate administered with food. Given the topical activity of lanthanum in the gut, and the excretion in feces of the majority of the dose, supportive therapy is recommended for overdosage. Lanthanum carbonate was not acutely toxic in animals by the oral route. No deaths and no adverse effects occurred in mice, rats or dogs after single oral doses of 2000 mg/kg (1.7, 3.4, and 11.3 times the MRHD, respectively, on a mg/m basis).
Fosrenol () Description
Fosrenol () contains lanthanum carbonate (2:3) hydrate with molecular formula La(CO) xHO (on average x=4-5 moles of water) and molecular weight 457.8 (anhydrous mass). Lanthanum (La) is a naturally occurring rare earth element. Lanthanum carbonate is practically insoluble in water.
Each Fosrenol () , white to off-white, chewable tablet contains lanthanum carbonate hydrate equivalent to 500, 750, or 1000 mg of elemental lanthanum and the following inactive ingredients: colloidal silicon dioxide NF, dextrates (hydrated) NF, magnesium stearate NF.
Fosrenol () does not contain calcium or aluminum.
Fosrenol () Clinical Pharmacology
In vitro
In five Phase I pharmacodynamic studies comparing the reduction from baseline of urinary phosphorus excretion in healthy volunteers (N=143 taking lanthanum carbonate), it was shown that the mean intestinal phosphate binding capacity of lanthanum ranged from 235 to 468 mg phosphorus/day when lanthanum was administered at a dose of 3 g per day with food. By comparison, in one study with an untreated control group (n=10) and another study with a placebo group (n=3), the corresponding mean changes from baseline were 3 mg phosphorus/day and 87 mg phosphorus/day, respectively.
Absorption and Distribution
max
In animal studies, lanthanum concentrations in several tissues, particularly gastrointestinal tract, mesenteric lymph nodes, bone and liver, increased over time to levels several orders of magnitude higher than those in plasma. The level of lanthanum in the liver was higher in renally impaired rats due to higher intestinal absorption. Lanthanum was found in the lysosomes and the biliary canal consistent with transcellular transport. Steady state tissue concentrations in bone and liver were achieved in dogs between 4 and 26 weeks. Relatively high levels of lanthanum remained in these tissues for longer than 6 months after cessation of dosing in dogs. There is no evidence from animal studies that lanthanum crosses the blood-brain barrier.
In 105 bone biopsies from patients treated with Fosrenol () for up to 4.5 years, rising levels of lanthanum were noted over time. Estimates of elimination half-life from bone ranged from 2.0 to 3.6 years. Steady state bone concentrations were not reached during the period studied.
Metabolism and Elimination
No information is available regarding the mass balance of lanthanum in humans after oral administration. In rats and dogs, the mean recovery of lanthanum after an oral dose was about 99% and 94%, respectively, and was essentially all from feces. Biliary excretion is the predominant route of elimination for circulating lanthanum in rats. In healthy volunteers administered intravenous lanthanum as the soluble chloride salt (120 μg), renal clearance was less than 2% of total plasma clearance. Quantifiable amounts of lanthanum were not measured in the dialysate of treated ESRD patients.
Drug Interactions
Fosrenol () has a low potential for systemic drug-drug interactions because of the very low bioavailability of lanthanum and because it is not a substrate or inhibitor of major cytochrome P450 enzyme groups involved in drug metabolism (CYP1A2, CYP2C9/10, CYP2C19, CYP2D6 and CYP3A4/5).
Fosrenol () does not alter gastric pH. Therefore, Fosrenol () drug interactions based on altered gastric pH are not expected.
In an investigation, lanthanum did not form insoluble complexes when mixed in simulated gastric fluid with warfarin, digoxin, furosemide, phenytoin, metoprolol and enalapril. Clinical studies have shown that Fosrenol () (three doses of 1000 mg on the day prior to exposure and one dose of 1000 mg on the day of co-administration) administered 30 minutes earlier did not alter the pharmacokinetics of oral warfarin (10 mg), digoxin (0.5 mg), or metoprolol (100 mg). Potential pharmacodynamic interactions between lanthanum and these drugs (e.g., bleeding time or prothrombin time) were not evaluated. None of the drug interaction studies were done with the maximum recommended therapeutic dose of lanthanum carbonate. No drug interaction studies assessed the effects of drugs on phosphate binding by lanthanum carbonate.
Ciprofloxacin
In a randomized, two-way crossover study in healthy volunteers examining the interaction potential of a single oral dose of ciprofloxacin (750 mg) alone and with lanthanum carbonate (1 g TID), the maximum plasma concentration of ciprofloxacin was reduced by 56% and the area under the ciprofloxacin plasma concentration-time curve was reduced by 54%. The 24-h urinary recovery of ciprofloxacin was reduced 52% by Fosrenol () [].
Levothyroxine
In a single-dose crossover study of levothyroxine (1 mg) with or without simultaneous administration of a single dose of Fosrenol () (500 mg) in six euthyroid normal healthy volunteers, the area under the serum T4 concentration-time curve was decreased by 40% [].
Fat Soluble Vitamins
Fosrenol () appears not to affect the availability of fat soluble vitamins (A, D, E and K) or other nutrients [].
Citrate
Citrate did not increase the absorption of lanthanum.
Fosrenol () Nonclinical Toxicology
Oral administration of lanthanum carbonate to rats for up to 104 weeks, at doses up to 1500 mg of the salt per kg/day [2.5 times the MRHD of 5725 mg, on a mg/m basis, assuming a 60-kg patient] revealed no evidence of carcinogenic potential. In the mouse, oral administration of lanthanum carbonate for up to 99 weeks, at a dose of 1500 mg/kg/day (1.3 times the MRHD) was associated with an increased incidence of glandular stomach adenomas in male mice.
Lanthanum carbonate tested negative for mutagenic activity in an Ames assay using Salmonella typhimurium and Escherichia coli strains and HGPRT gene mutation and chromosomal aberration assays in Chinese hamster ovary cells. Lanthanum carbonate also tested negative in an oral mouse micronucleus assay at doses up to 2000 mg/kg (1.7 times the MRHD), and in micronucleus and unscheduled DNA synthesis assays in rats given IV lanthanum chloride at doses up to 0.1 mg/kg, a dose that produced plasma lanthanum concentrations >2000 times the peak human plasma concentration.
Lanthanum carbonate, at doses up to 2000 mg/kg/day (3.4 times the MRHD), did not affect fertility or mating performance of male or female rats.
Fosrenol () Clinical Studies
The effectiveness of Fosrenol () in reducing serum phosphorus in ESRD patients was demonstrated in one short-term, placebo-controlled, double-blind dose-ranging study, two placebo-controlled randomized withdrawal studies and two long-term, active-controlled, open-label studies in both hemodialysis and peritoneal dialysis (PD) patients.
One hundred and forty-four patients with chronic renal failure undergoing hemodialysis and with elevated phosphate levels were randomized to double-blind treatment at a fixed dose of lanthanum carbonate of 225 mg (n=27), 675 mg (n=29), 1350 mg (n=30) or 2250 mg (n=26) or placebo (n=32) in divided doses with meals. Fifty-five percent of subjects were male, 71% black, 25% white and 4% of other races. The mean age was 56 years and the duration of dialysis ranged from 0.5 to 15.3 years. Steady-state effects were achieved after two weeks. The effect after six weeks of treatment is shown in Figure 1.
Figure 1. Difference in Phosphate Reduction in the Fosrenol () and Placebo Group in a 6-Week, Dose-Ranging, Double-Blind Study in ESRD Patients (with 95% Confidence Intervals)
One-hundred and eighty-five patients with end stage renal disease undergoing either hemodialysis (n=146) or peritoneal dialysis (n=39) were enrolled in two placebo-controlled, randomized withdrawal studies. Sixty-four percent of subjects were male, 28% black, 62% white and 10% of other races. The mean age was 58.4 years and the duration of dialysis ranged from 0.2 to 21.4 years. After titration of lanthanum carbonate to achieve a phosphate level between 4.2 and 5.6 mg/dL in one study (doses up to 2250 mg/day) or 5.9 mg/dL in the second study (doses up to 3000 mg/day) and maintenance through 6 weeks, patients were randomized to lanthanum or placebo. During the placebo-controlled, randomized withdrawal phase (four weeks), the phosphorus concentration rose in the placebo group by 1.9 mg/dL in both studies relative to patients who remained on lanthanum carbonate therapy.
Two long-term open-label studies were conducted, involving a total of 2028 patients with ESRD undergoing hemodialysis. Patients were randomized to receive Fosrenol () or alternative phosphate binders for up to six months in one study and two years in the other. The daily Fosrenol () doses, divided and taken with meals, ranged from 375 mg to 3000 mg. Doses were titrated to reduce serum phosphate levels to a target level. The daily doses of the alternative therapy were based on current prescribing information or those commonly utilized. Both treatment groups had similar reductions in serum phosphate of about 1.8 mg/dL. Maintenance of reduction was observed for up to three years in patients treated with Fosrenol () in long-term, open-label extensions.
No effects of Fosrenol () on serum levels of 25-dihydroxy vitamin D3, vitamin A, vitamin B12, vitamin E and vitamin K were observed in patients who were monitored for 6 months.
Paired bone biopsies (at baseline and at one or two years) in 69 patients randomized to either Fosrenol () or calcium carbonate in one study and 99 patients randomized to either Fosrenol () or alternative therapy in a second study showed no differences in the development of mineralization defects between the groups.
Vital status was known for over 2000 patients, 97% of those participating in the clinical program during and after receiving treatment. The adjusted yearly mortality rate (rate/years of observation) for patients treated with Fosrenol () or alternative therapy was 6.6%.
Fosrenol () How Supplied/storage And Handling
Fosrenol () is supplied as a chewable tablet in three dosage strengths for oral administration: 500 mg tablets, 750 mg tablets, and 1000 mg tablets. Each chewable tablet is white to off-white round, flat with a bevelled edge, and debossed on one side with 'S405' and the dosage strength corresponding to the content of elemental lanthanum.
500 mg Patient Pack (2 bottles of 45 tablets, NDC 54092-252-45, per each patient pack) NDC 54092-252-90.
750 mg Patient Pack (6 bottles of 15 tablets, NDC 54092-253-15, per each patient pack) NDC 54092-253-90.
1000 mg Patient Pack (9 bottles of 10 tablets, NDC 54092-254-10, per each patient pack) NDC 54092-254-90.
Storage - Store at 25°C (77°F): excursions permitted to 15-30°C (59-86°F).
[See USP controlled room temperature].
Protect from moisture.
Fosrenol () Patient Counseling Information
Advise patients to take Fosrenol () tablets with or immediately after meals. It should be emphasized that Fosrenol () tablets should not be swallowed intact. Consider crushing tablets completely for patients with poor dentition. [].
Advise patients who are taking an oral medication where a reduction in the bioavailability of that medication would have a clinically significant effect on its safety or efficacy to separate the dosing of Fosrenol () from the dosing of the affected drug by several hours [].
Advise patients to notify their physician that they are taking Fosrenol () prior to an abdominal x-ray. []
Manufactured by DSM Pharmaceuticals Inc.,
5900 NW Greenville Blvd,
Greenville, NC 27834
Manufactured for Shire US Inc., Wayne, PA 19087.
Fosrenol () is a trademark of Shire LLC.
©2011 Shire Pharmaceuticals Inc.
This product is covered by US patent 5,968,976
Last Modified: 08/2011
Fosrenol () Medication Guide
Read this Medication Guide before you start taking Fosrenol () and each time you get a refill. There may be new information. This information does not take the place of talking to your healthcare provider about your medical condition or treatment.
Fosrenol () may cause a bowel blockage or severe constipation which can be serious, and sometimes lead to surgery or treatment in a hospital.
- a history of bowel surgery or colon cancer
- a history of bowel blockage, decreased movement of your bowel, constipation, or diabetes
Fosrenol () is a prescription medicine used in people with end stage renal disease (ESRD) to lower the amount of phosphate in the blood.
Do not take Fosrenol () if you:
Fosrenol () has not been studied in children and adolescents under 18 years of age.
Especially tell your healthcare provider if you take:
Know the medicines you take. Keep a list of them and show it to your healthcare provider and pharmacist when you get a new medicine.
See
Tell your healthcare provider if you have any side effect that bothers you or that does not go away.
These are not all the side effects of Fosrenol () . For more information, ask your healthcare provider or pharmacist.
Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use Fosrenol () for a condition for which it was not prescribed. Do not give Fosrenol () to other people, even if they have the same condition. It may harm them.
This Medication Guide summarizes the most important information about Fosrenol () . If you would like more information, talk with your healthcare provider. You can ask your pharmacist or healthcare provider for information about Fosrenol () that is written for healthcare professionals.
For more information go to www.Fosrenol () .com or call 1-800-828-2088.
© 2011 Shire US Inc.
Wayne, PA 19087
Issued [08/2011]
