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Professional Information — Phoslo

Full FDA prescribing details for healthcare professionals.

Last updated · May 15, 2026Source: DailyMed ↗
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Indications and Usage

PhosLo is indicated for the control of hyperphosphatemia in end stage renal failure and does not promote aluminum absorption.

Dosage and Administration

The recommended initial dose of PhosLo for the adult dialysis patient is 2 gelcaps with each meal. The dosage may be increased gradually to bring the serum phosphate value below 6 mg/dl, as long as hypercalcemia does not develop. Most patients require 3-4 gelcaps with each meal.

Contraindications

Patients with hypercalcemia.

Adverse Reactions

In clinical studies, patients have occasionally experienced nausea during PhosLo therapy. Hypercalcemia may occur during treatment with PhosLo. Mild hypercalcemia (Ca>10.5mg/dl) may be asymptomatic or manifest itself as constipation, anorexia, nausea and vomiting. More severe hypercalcemia (Ca>12mg/dl) is associated with confusion, delirium, stupor and coma. Mild hypercalcemia is easily controlled by reducing the PhosLo dose or temporarily discontinuing therapy. Severe hypercalcemia can be treated by acute hemodialysis and discontinuing PhosLo therapy. Decreasing dialysate calcium concentration could reduce the incidence and severity of PhosLo induced hypercalcemia. The long-term effect of PhosLo on the progression of vascular or soft tissue calcification has not been determined.

Isolated cases of pruritus have been reported which may represent allergic reactions.

Overdosage

Administration of PhosLo in excess of the appropriate daily dosage can cause severe hypercalcemia (see ADVERSE REACTIONS section).

Description

Each opaque gelcap with a blue cap and white body is spin printed in blue and white ink with “PhosLo®” printed on the cap and “667 mg” printed on the body. Each gelcap contains 667 mg calcium acetate, USP (anhydrous; Ca(CH3COO)2; MW=158.17 grams) equal to 169 mg (8.45 mEq) calcium, and 10 mg of the inert binder, polyethylene glycol 8000 NF. The gelatin cap and body have the following inactive ingredients: FD&C blue #1, D&C red #28, titanium dioxide, USP and gelatin, USP.

PhosLo Gelcaps (calcium acetate) are administered orally for the control of hyperphosphatemia in end stage renal failure.

Clinical Pharmacology

Patients with advanced renal insufficiency (creatinine clearance less than 30 ml/min) exhibit phosphate retention and some degree of hyperphosphatemia. The retention of phosphate plays a pivotal role in causing secondary hyperparathyroidism associated with osteodystrophy, and soft-tissue calcification. The mechanism by which phosphate retention leads to hyperparathyroidism is not clearly delineated. Therapeutic efforts directed toward the control of hyperphosphatemia include reduction in the dietary intake of phosphate, inhibition of absorption of phosphate in the intestine with phosphate binders, and removal of phosphate from the body by more efficient methods of dialysis. The rate of removal of phosphate by dietary manipulation or by dialysis is insufficient. Dialysis patients absorb 40% to 80% of dietary phosphorus. Therefore, the fraction of dietary phosphate absorbed from the diet needs to be reduced by using phosphate binders in most renal failure patients on maintenance dialysis. Calcium acetate (PhosLo) when taken with meals, combines with dietary phosphate to form insoluble calcium phosphate which is excreted in the feces. Maintenance of serum phosphorus below 6.0 mg/dl is generally considered as a clinically acceptable outcome of treatment with phosphate binders. PhosLo is highly soluble at neutral pH, making the calcium readily available for binding to phosphate in the proximal small intestine.

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

How Supplied / Storage and Handling

Gelcap: A white and blue gelcap for oral administration containing 667 mg calcium acetate (anhydrous Ca(CH3COO)2; MW=158.17 grams) equal to 169 mg (8.45 mEq) calcium.

Gelcap

NDC 54868-5691-0 Bottles of 200

NDC 54868-5691-1 Bottles of 100


STORAGE

Store at 25°C (77°F); excursions permitted to 15-30°C (59-86°F). See USP “Controlled Room Temperature.”

Rx only

Manufactured for
Fresenius Medical Care
Waltham, MA 02451

100623.00    01/07


Repackaging and Relabeling by:
Physicians Total Care, Inc.
Tulsa, OK    74146

Sources

RxCUI: 645216

NDC: 492300640

Last fetched: May 15, 2026

Source: DailyMed ↗

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This information is for educational purposes only and is not medical advice. Always consult your doctor, pharmacist, or other licensed healthcare professional before starting, stopping, or changing any medicine. Read full medical disclaimer.