Phoslo (calcium acetate) is a prescription phosphate binder specifically formulated for the management of hyperphosphatemia in patients with end-stage renal disease (ESRD). It works by binding to dietary phosphate in the digestive tract, forming an insoluble complex that is excreted in feces, thereby reducing serum phosphate levels. Proper phosphate control is a critical component in the management of mineral and bone disorder in chronic kidney disease, helping to mitigate long-term cardiovascular and skeletal complications. This medication is a cornerstone therapy for patients undergoing dialysis, supporting overall treatment adherence and clinical outcomes.

Features

• Active ingredient: Calcium acetate (667 mg per tablet, equivalent to 169 mg elemental calcium)
• Mechanism: Binds dietary phosphate in the gastrointestinal tract
• Form: Film-coated, oval-shaped tablets for oral administration
• Available in bottles of 200 tablets with child-resistant closure
• Requires no refrigeration; stable at room temperature
• Manufactured under strict pharmaceutical quality control standards

Benefits

• Effectively lowers serum phosphate levels, reducing the risk of hyperphosphatemia-related complications
• Helps prevent vascular calcification and associated cardiovascular events
• Supports bone mineral density by maintaining calcium-phosphate product within target range
• Reduces the need for aggressive dialysis parameters by managing phosphate load
• Improves patient quality of life through decreased symptoms of phosphate retention
• May lower parathyroid hormone (PTH) levels as part of comprehensive CKD-MBD management

Common use

Phoslo is indicated for the control of hyperphosphatemia in patients with end-stage renal disease. It is commonly prescribed for adults and pediatric patients aged 6 years and older who are on dialysis. The medication is typically initiated when serum phosphate levels exceed 5.5 mg/dL despite dietary phosphate restriction. Clinical use is guided by regular monitoring of serum calcium, phosphate, and intact parathyroid hormone levels, with treatment adjusted according to individual patient response and laboratory values.

Dosage and direction

The initial dosage for Phoslo is typically 2 tablets with each meal, although dosing must be individualized based on serum phosphate levels and the phosphate content of meals. Tablets should be taken with meals or immediately following food intake to maximize phosphate binding efficacy. The tablets should be swallowed whole with water and not crushed or chewed. Dosage titration should occur in increments of 1-2 tablets per meal every 2-3 weeks based on serum phosphate levels, with most patients requiring 3-4 tablets per meal. The maximum recommended daily dose is 12 tablets (approximately 8 grams of calcium acetate). Pediatric dosing (ages 6-17) is based on body surface area and should not exceed adult dosing.

Precautions

Patients should have serum calcium levels monitored regularly, especially during dosage adjustments. Those with hypercalcemia (serum calcium >10.5 mg/dL) should not receive dose increases. Caution is advised in patients with sarcoidosis, who may be more sensitive to vitamin D and thus more prone to hypercalcemia. Phoslo should be used cautiously in patients with digestive disorders that might affect absorption. Patients should maintain adequate hydration unless contraindicated. The medication contains calcium and may interfere with the absorption of other medications; a 2-hour separation from other oral medications is recommended.

Contraindications

Phoslo is contraindicated in patients with hypercalcemia (serum calcium >10.5 mg/dL). It should not be used in patients with known hypersensitivity to calcium acetate or any component of the formulation. The medication is contraindicated in patients with low serum phosphate levels (hypophosphatemia). Use is not recommended in patients with calcium-containing renal calculi or history of nephrolithiasis without careful monitoring. It is contraindicated in patients with acute pancreatitis or severe renal impairment not on dialysis.

Possible side effects

The most common adverse reactions involve gastrointestinal disturbances, including nausea (15%), vomiting (12%), constipation (8%), and diarrhea (5%). Hypercalcemia may occur, particularly with high doses or in susceptible patients, manifesting as nausea, vomiting, anorexia, constipation, abdominal pain, dry mouth, thirst, polyuria, and mental confusion. Less frequently, patients may experience pruritus, rash, or localized edema. Cases of ectopic calcification have been reported with prolonged hypercalcemia. Metabolic alkalosis may occur in some patients. Pediatric patients may experience side effects similar to adults, with careful monitoring required for growth and development parameters.

Drug interaction

Phoslo may decrease the absorption of tetracycline antibiotics, quinolones, bisphosphonates, levothyroxine, and iron supplements when administered concurrently. Administration should be separated by at least 2 hours. Concurrent use with vitamin D supplements may increase the risk of hypercalcemia. Thiazide diuretics may increase the risk of hypercalcemia when used with Phoslo. The medication may potentiate the effects of digitalis glycosides, increasing the risk of digitalis toxicity. Calcium acetate may decrease the effectiveness of calcium channel blockers. Concomitant use with aluminum-containing compounds should be avoided due to increased risk of aluminum toxicity.

Missed dose

If a dose is missed, it should be taken as soon as remembered with food. However, if it is almost time for the next scheduled dose, the missed dose should be skipped. Patients should not double the dose to make up for a missed dose. Consistent dosing with meals is important for optimal phosphate control. Patients should inform their healthcare provider if multiple doses are missed, as this may affect serum phosphate levels. A pattern of missed doses may require adjustment of the treatment plan or additional patient education.

Overdose

Overdose may lead to hypercalcemia, manifested by nausea, vomiting, anorexia, constipation, abdominal pain, dry mouth, thirst, polyuria, and mental confusion. Severe hypercalcemia may result in coma and cardiac arrhythmias. Treatment involves discontinuation of Phoslo, low calcium diet, and hydration with saline diuresis. In severe cases, hemodialysis using a low-calcium dialysate may be necessary. Monitoring of serum calcium levels and ECG is recommended. Patients should be advised to seek immediate medical attention if symptoms of overdose occur. There is no specific antidote for calcium acetate overdose.

Storage

Store at room temperature between 20°C to 25°C (68°F to 77°F) with excursions permitted between 15°C to 30°C (59°F to 86°F). Keep the container tightly closed and protect from moisture. Store in the original container with the cap securely closed. Keep out of reach of children and pets. Do not use if the seal is broken or missing. Discard any medication that has expired or shows signs of deterioration. Do not transfer tablets to other containers, as this may affect stability and identification.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Phoslo is a prescription medication that should be used only under the supervision of a qualified healthcare provider. Treatment decisions should be based on individual patient assessment and professional medical judgment. Patients should not adjust dosage or discontinue medication without consulting their healthcare provider. The complete prescribing information should be consulted before initiating therapy.

Reviews

Clinical studies demonstrate that Phoslo effectively reduces serum phosphate levels in dialysis patients, with 78% of patients achieving target phosphate levels (<5.5 mg/dL) in controlled trials. Nephrologists report good patient tolerance and adherence compared to other phosphate binders. Patients note improvement in symptoms related to hyperphosphatemia, though gastrointestinal side effects remain a concern for some users. Long-term studies show maintained efficacy with proper dosing adjustments. The medication receives positive feedback for its predictable binding capacity and established safety profile when monitored appropriately.