Calcium Acetate

1. INDICATIONS & USAGE Calcium acetate capsules are a phosphate binder indicated to reduce serum phosphorus in patients with end stage renal disease (ESRD). Calcium acetate capsules are a phosphate binder indicated for the reduction of serum phosphorus in patients with end stage renal disease. ( 1 )

2. DOSAGE & ADMINISTRATION The recommended initial dose of calcium acetate capsules for the adult dialysis patient is 2 capsules with each meal. Increase the dose gradually to lower serum phosphorus levels to the target range, as long as hypercalcemia does not develop. Most patients require 3-4 capsules with each meal. Starting dose is 2 capsules with each meal. ( 2 ) Titrate the dose every 2-3 weeks until acceptable serum phosphorus level is reached. Most patients require 3-4 capsules with each meal. ( 2 )

3. DOSAGE FORMS & STRENGTHS Capsule: 667 mg calcium acetate, USP per capsule. Capsule: 667 mg calcium acetate ( 3 )

4. CONTRAINDICATIONS Patients with hypercalcemia. Hypercalcemia. ( 4 )

5. WARNINGS AND PRECAUTIONS Treat mild hypercalcemia by reducing or interrupting calcium acetate capsules and Vitamin D. Severe hypercalcemia may require hemodialysis and discontinuation of calcium acetate capsules. ( 5.1 ) Hypercalcemia may aggravate digitalis toxicity. ( 5.2 )

5.1 Hypercalcemia Patients with end stage renal disease may develop hypercalcemia when treated with calcium, including calcium acetate (calcium acetate capsules). Avoid the use of calcium supplements, including calcium-based nonprescription antacids, concurrently with calcium acetate capsules. An overdose of calcium acetate capsules may lead to progressive hypercalcemia, which may require emergency measures. Therefore, early in the treatment phase during the dosage adjustment period, monitor serum calcium levels twice weekly. Should hypercalcemia develop, reduce the calcium acetate capsules dosage or discontinue the treatment, depending on the severity of hypercalcemia. More severe hypercalcemia (Ca>12 mg/dL) is associated with confusion, delirium, stupor and coma. Severe hypercalcemia can be treated by acute hemodialysis and discontinuing calcium acetate capsules therapy. Mild hypercalcemia (10.5 to 11.9 mg/dL) may be asymptomatic or manifest as constipation, anorexia, nausea, and vomiting. Mild hypercalcemia is usually controlled by reducing the calcium acetate capsules dose or temporarily discontinuing therapy. Decreasing or discontinuing Vitamin D therapy is recommended as well. Chronic hypercalcemia may lead to vascular calcification and other soft-tissue calcification. Radiographic evaluation of suspected anatomical regions may be helpful in early detection of soft tissue calcification. The long term effect of calcium acetate capsules on the progression of vascular or soft tissue calcification has not been determined. Hypercalcemia (>11 mg/dL) was reported in 16% of patients in a 3-month study of solid dose formulation of calcium acetate; all cases resolved upon lowering the dose or discontinuing treatment. Maintain the serum calcium-phosphorus (Ca × P) product below 55 mg2/dL2.

5.2 Concomitant Use with Medications Hypercalcemia may aggravate digitalis toxicity.

7. DRUG INTERACTIONS The drug interaction of calcium acetate capsules is characterized by the potential of calcium to bind to drugs with anionic functions (e.g., carboxyl and hydroxyl groups). Calcium acetate capsules may decrease the bioavailability of tetracyclines or fluoroquinolones via this mechanism. There are no empirical data on avoiding drug interactions between calcium acetate or calcium acetate capsules and most concomitant drugs. When administering an oral medication with calcium acetate capsules where a reduction in the bioavailability of that medication would have a clinically significant effect on its safety or efficacy, administer the drug one hour before or three hours after calcium acetate capsules or calcium acetate. Monitor blood levels of the concomitant drugs that have a narrow therapeutic range. Patients taking anti-arrhythmic medications for the control of arrhythmias and anti-seizure medications for the control of seizure disorders were excluded from the clinical trials with all forms of calcium acetate. Calcium acetate capsules may decrease the bioavailability of tetracyclines or fluoroquinolones. ( 7 ) When clinically significant drug interactions are expected, administer the drug at least one hour before or at least three hours after calcium acetate capsules, or consider monitorinG blood levels of the drug. ( 7 )

7.1 Ciprofloxacin In a study of 15 healthy subjects, a co-administered single dose of 4 calcium acetate tablets approximately 2.7 g decreased the bioavailability of ciprofloxacin by approximately 50%.

6. ADVERSE REACTIONS Hypercalcemia is discussed elsewhere [see Warnings and Precautions (5.1) ] The most common (> 10%) adverse reactions are hypercalcemia, nausea, and vomiting. ( 6.1 ) In clinical studies, patients have occasionally experienced nausea during calcium acetate therapy. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact AvKARE at 1-855-361-3993 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch 6.1 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. In clinical studies, calcium acetate has been generally well tolerated. Calcium acetate capsules were studied in a 3-month, open-label, non-randomized study of 98 enrolled ESRD hemodialysis patients and in a two week double-blind, placebo-controlled, crossover study with 69 enrolled ESRD hemodialysis patients. Adverse reactions (>2% on treatment) from these trials are presented in Table 1. Table 1: Adverse Reactions in Patients with End-Stage Renal Disease Undergoing Hemodialysis Preferred Term Total adverse reactions reported for calcium acetate n=167 (n%) 3-mo, open-label study of calcium acetate n=98 (n%) Double blind, placebo-controlled, cross-over study of calcium acetate n=69 Calcium acetate (n%) Placebo (n%) Nausea 6 (3.6) 6 (6.1) 0 (0.0) 0 (0.0) Vomiting 4 (2.4) 4 (4.1) 0 (0.0) 0 (0.0) Hypercalcemia 21 (12.6) 16 (16.3) 5 (7.2) 0 (0.0) Mild hypercalcemia may be asymptomatic or manifest itself as constipation, anorexia, nausea, and vomiting. More severe hypercalcemia is associated with confusion, delirium, stupor, and coma. Decreasing dialysate calcium concentration could reduce the incidence and severity of calcium acetate capsules induced hypercalcemia. Isolated cases of pruritus have been reported, which may represent allergic reactions.

6.2 Postmarketing Experience Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to estimate their frequency or to establish a causal relationship to drug exposure. The following additional adverse reactions have been identified during post-approval of calcium acetate: dizziness, edema, and weakness. To report SUSPECTED ADVERSE REACTIONS, contact AvKARE at 1-855-361-3993 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

10. OVERDOSAGE Administration of calcium acetate capsules in excess of the appropriate daily dosage may result in hypercalcemia [see Warnings and Precautions (5.1) ]

8. USE IN SPECIFIC POPULATIONS 8.1 PREGNANCY Pregnancy Category C Calcium acetate capsules contain calcium acetate. Animal reproduction studies have not been conducted with calcium acetate capsules, and there are no adequate and well controlled studies of calcium acetate capsules use in pregnant women. Patients with end stage renal disease may develop hypercalcemia with calcium acetate treatment [see Warnings and Precautions (5.1) ]. Maintenance of normal serum calcium levels is important for maternal and fetal well being. Hypercalcemia during pregnancy may increase the risk for maternal and neonatal complications such as stillbirth, preterm delivery, and neonatal hypocalcemia and hypoparathyroidism. Calcium acetate capsules treatment, as recommended, is not expected to harm a fetus if maternal calcium levels are properly monitored during and following treatment.

8.2 LABOR & DELIVERY The effects of calcium acetate capsules on labor and delivery are unknown.

8.3 NURSING MOTHERS Calcium acetate capsules contain calcium acetate and is excreted in human milk. Human milk feeding by a mother receiving calcium acetate capsules is not expected to harm an infant, provided maternal serum calcium levels are appropriately monitored.

8.4 PEDIATRIC USE Safety and effectiveness in pediatric patients have not been established.

8.5 GERIATRIC USE Clinical studies of calcium acetate did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

Pregnancy Category C Calcium acetate capsules contain calcium acetate. Animal reproduction studies have not been conducted with calcium acetate capsules, and there are no adequate and well controlled studies of calcium acetate capsules use in pregnant women. Patients with end stage renal disease may develop hypercalcemia with calcium acetate treatment [see Warnings and Precautions (5.1) ]. Maintenance of normal serum calcium levels is important for maternal and fetal well being. Hypercalcemia during pregnancy may increase the risk for maternal and neonatal complications such as stillbirth, preterm delivery, and neonatal hypocalcemia and hypoparathyroidism. Calcium acetate capsules treatment, as recommended, is not expected to harm a fetus if maternal calcium levels are properly monitored during and following treatment.

Calcium acetate capsules contain calcium acetate and is excreted in human milk. Human milk feeding by a mother receiving calcium acetate capsules is not expected to harm an infant, provided maternal serum calcium levels are appropriately monitored.

Safety and effectiveness in pediatric patients have not been established.

Clinical studies of calcium acetate did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

11. DESCRIPTION Calcium acetate capsules, USP act as a phosphate binder. Its chemical name is calcium acetate. Its molecular formula is C 4 H 6 CaO 4 , and its molecular weight is 158.17. Its structural formula is: Each capsule for oral administration contains 667 mg of calcium acetate, USP (anhydrous; Ca(CH 3 COO) 2 ; MW=158.17 grams) equivalent to 169 mg (8.45 mEq) of calcium and the inactive ingredients magnesium stearate and polyethylene glycol. The capsules are size 00EL with light green opaque cap and white opaque body with black imprint on cap "NC" above "667". The gelatin capsules contain D&C Yellow #10, FD&C Blue #1, FD&C Red #40, titanium dioxide and gelatin. The imprinting ink contains the following: black iron oxide, D&C Yellow # 10 Aluminum Lake, FD&C Blue #1/ Brilliant Blue FCF Aluminum Lake, FD&C Blue #2/ Indigo Carmine Aluminum Lake, FD&C Red # 40/ Allura Red AC Aluminum Lake, propylene glycol and shellac glaze. USP dissolution test is pending. Chemical Structure

12. CLINICAL PHARMACOLOGY Patients with ESRD retain phosphorus and can develop hyperphosphatemia. High serum phosphorus can precipitate serum calcium resulting in ectopic calcification. Hyperphosphatemia also plays a role in the development of secondary hyperparathyroidism in patients with ESRD.

12.1 MECHANISM OF ACTION Calcium acetate (calcium acetate capsules) when taken with meals, combines with dietary phosphate to form an insoluble calcium phosphate complex, which is excreted in the feces, resulting in decreased serum phosphorus concentration.

12.2 PHARMACODYNAMICS Orally administered calcium acetate from pharmaceutical dosage forms is systemically absorbed up to approximately 40% under fasting conditions and up to approximately 30% under non-fasting conditions. This range represents data from both healthy subjects and renal dialysis patients under various conditions.

Calcium acetate (calcium acetate capsules) when taken with meals, combines with dietary phosphate to form an insoluble calcium phosphate complex, which is excreted in the feces, resulting in decreased serum phosphorus concentration.

Orally administered calcium acetate from pharmaceutical dosage forms is systemically absorbed up to approximately 40% under fasting conditions and up to approximately 30% under non-fasting conditions. This range represents data from both healthy subjects and renal dialysis patients under various conditions.

& MUTAGENESIS & IMPAIRMENT OF FERTILITY No carcinogenicity, mutagenicity, or fertility studies have been conducted with calcium acetate.

17. PATIENT COUNSELING INFORMATION Inform patients to take calcium acetate capsules with meals, adhere to their prescribed diets, and avoid the use of calcium supplements including nonprescription antacids. Inform the patients about the symptoms of hypercalcemia [see Warnings and Precautions (5.1) and Adverse Reactions (6.1) ] Advise patients who are taking an oral medication where reduction in the bioavailability of that medication would have clinically significant effect on its safety and efficancy to take the drug one hour before or three hours after calcium acetate capsules.

STORAGE: Store at 20-25°C (68-77°F); excursions permitted to 15-30°C (59-86°F) [See USP "Controlled Room Temperature"].