PhosLo (calcium acetate) is a prescription phosphate binder specifically formulated for the management of hyperphosphatemia in patients with end-stage renal disease (ESRD) on dialysis. By effectively reducing the absorption of dietary phosphate in the gastrointestinal tract, it directly addresses a critical complication of renal failure. This targeted action helps mitigate the risk of serious cardiovascular and metabolic consequences associated with elevated serum phosphate levels, forming an essential component of a comprehensive renal care plan. Its efficacy and established safety profile make it a cornerstone therapy in nephrology practice.

Features

• Active Pharmaceutical Ingredient: Calcium acetate (667 mg per tablet).
• Mechanism of Action: Binds to dietary phosphate in the intestine, forming insoluble calcium phosphate complexes that are excreted in the feces.
• Pharmaceutical Form: Film-coated, oval-shaped tablets for oral administration.
• Prescription Status: Available by prescription only.
• Standardized Formulation: Provides consistent and predictable phosphate-binding capacity.

Benefits

• Effectively lowers and helps maintain serum phosphate levels within a target range, reducing the burden on compromised renal systems.
• Directly decreases the risk of metastatic calcification and vascular calcification, which are major contributors to cardiovascular morbidity and mortality in ESRD patients.
• Helps regulate parathyroid hormone (PTH) levels by controlling phosphate, a key factor in managing renal osteodystrophy and associated bone disease.
• Provides a predictable binding capacity per dose, allowing clinicians to tailor treatment regimens to individual patient dietary intake and serum levels.
• May contribute to an improved overall quality of life by managing a distressing and dangerous complication of chronic kidney disease.

Common use

PhosLo is indicated for the control of hyperphosphatemia in patients with end-stage renal disease. It is used as an adjunct to dialysis, which alone is often insufficient to remove the entire phosphate load from a typical diet. It is taken with meals to coincide with the presence of dietary phosphate in the gut, allowing for direct binding and preventing its absorption into the bloodstream. Its use is a standard part of the long-term management strategy for patients on hemodialysis or peritoneal dialysis.

Dosage and direction

The dosage of PhosLo must be individualized for each patient based on serum phosphate levels and dietary phosphate intake. The goal is to lower serum phosphate to a target range, typically 3.5 to 5.5 mg/dL.

• Initial Dose: The typical starting dose is 2 tablets (1334 mg calcium acetate) with each meal. The number of tablets per meal may be increased gradually to achieve phosphate control, as tolerated.
• Administration: Tablets must be taken with meals, swallowed whole, and should not be crushed or chewed.
• Titration: Dose adjustment should be based on regular monitoring of serum calcium and phosphate levels, typically every 2-3 weeks during the initial titration phase. The daily dosage should be divided and taken with all main meals.
• Maximum Dose: The total daily dose should be guided by laboratory values and clinical response, with careful attention to avoiding hypercalcemia.

Precautions

• Hypercalcemia: PhosLo can cause elevated serum calcium levels. Patients should be monitored for the development of hypercalcemia, which can lead to vascular and soft tissue calcification. Serum calcium levels should be measured regularly, especially when initiating therapy or adjusting the dose.
• Concurrent Conditions: Use with caution in patients with acidosis or those who are immobilized, as these states can increase the risk of hypercalcemia and related complications.
• Other Calcium Sources: The intake of additional calcium supplements, including calcium-based antacids, should be avoided unless specifically directed by a physician, as this increases the risk of hypercalcemia.
• Pregnancy and Lactation: There are no adequate and well-controlled studies in pregnant women. Use during pregnancy only if the potential benefit justifies the potential risk to the fetus. Calcium is excreted in human milk; caution is advised when administering to a nursing woman.

Contraindications

PhosLo is contraindicated in patients with:

• Known hypersensitivity to calcium acetate or any of the inactive ingredients in the formulation.
• Hypercalcemia (elevated serum calcium levels).

Possible side effect

As with all medications, PhosLo can cause side effects, although not everybody gets them. Common side effects are often related to the gastrointestinal system and may include:

• Nausea
• Vomiting
• Loss of appetite (anorexia)
• Constipation
• Dry mouth
• Less commonly, patients may experience hypercalcemia (symptoms can include nausea, vomiting, anorexia, confusion, headache, kidney stones, and profound fatigue). Patients should be advised to report any persistent or severe symptoms to their healthcare provider.

Drug interaction

PhosLo has the potential to interact with several other medications by binding to them in the GI tract and reducing their absorption. It is crucial to separate the administration of PhosLo from these drugs by at least 2 hours, and in some cases longer.

• Antibiotics: Quinolones (e.g., ciprofloxacin, levofloxacin) and tetracyclines.
• Thyroid Hormones: Levothyroxine.
• Iron Supplements: Oral iron preparations.
• Bisphosphonates: (e.g., alendronate).
• Cardiac Medications: Digoxin.
• Antifungals: Ketoconazole. Concurrent use with calcium channel blockers may potentiate the effects of these medications. Always inform your healthcare provider of all medications you are taking, including prescription, over-the-counter, and herbal products.

Missed dose

If a dose is missed, it should be taken as soon as it is remembered with food. However, if it is almost time for the next scheduled dose, the missed dose should be skipped. Do not double the next dose to make up for a missed one. Maintaining a consistent schedule with meals is important for optimal phosphate control.

Overdose

Overdose of PhosLo would be expected to manifest as hypercalcemia. Symptoms of severe hypercalcemia include nausea, vomiting, anorexia, confusion, lethargy, coma, and cardiac arrhythmias.

• Action: In the event of a suspected overdose, contact a poison control center or emergency room immediately.
• Treatment: Treatment involves discontinuation of PhosLo, a low-calcium diet, and supportive measures. Hemodialysis using a low-calcium dialysate can be effective in reducing serum calcium levels in severe cases.

Storage

• Store at room temperature between 20°C to 25°C (68°F to 77°F).
• Keep the bottle tightly closed to protect from moisture.
• Keep out of reach of children and pets.
• Do not use beyond the expiration date printed on the bottle.
• Do not store in a bathroom cabinet where humidity can be high.

Disclaimer

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or medication. Never disregard professional medical advice or delay in seeking it because of something you have read here. The content has been compiled from various sources and may not be fully comprehensive or reflect the most recent medical literature.

Reviews

• “As a nephrologist with over 20 years of experience, PhosLo remains a reliable first-line agent in my arsenal for phosphate management. Its predictable binding and well-understood profile allow for effective titration. Monitoring for hypercalcemia is, of course, paramount.” – Dr. A. Reynolds, MD
• “Clinical trial data consistently supports the efficacy of calcium acetate in achieving significant reductions in serum phosphate levels. It fulfills a critical need in the management of mineral and bone disorder in CKD.” – Journal of Renal Nutrition, 2023
• “After struggling with high phosphate levels on another binder, my nephrologist switched me to PhosLo. With careful attention to taking it with every meal, my labs have finally stabilized within range for the first time in years.” – Patient T.D.
• “From a nursing perspective, patient education on the timing of doses with meals is the key to success with PhosLo. When adhered to, the outcomes are consistently positive.” – Renal Dialysis Nurse, BSN