Be familiar with how to use phosphate binders

Expect sevelamer (Renagel) or lanthanum (Fosrenol) to be saved for patients with hypercalcemia.....
Mahitab Hany, BS Pharm, PGDipClinPharm, PGDipClinNutrition

As a nephrology pharmacy specialist, you will be asked how to manage hyperphosphatemia during transitions of care in patients with severe chronic kidney disease. High phosphorus levels cause hypocalcemia, which triggers parathyroid hormone release. This can lead to fractures, vascular calcification, and is linked to increased mortality.

Expect maintenance binders (see Table 1) to be saved for persistently elevated phosphate levels. Any binder can lower phosphorus levels by about 1 to 2 mg/dL, but none is shown to improve outcomes. Most patients will start with a calcium-based binder like calcium carbonate (Cal-Preg, Calcimate, etc) or acetate (Marcal, etc). They cost the least. Some experts avoid these due to concerns of vascular calcification. But recent evidence suggests calcium-based binders don't increase cardiovascular (CV) risk compared to those without calcium.

Table (1). Phosphorus binders
Phosphorus binder Dose Number of pills to reach PBED 6 g Formulation Advantages Disadvantages
Calcium carbonate 750–3500 mg 8 Swallowed and chewable tablets Low cost, over-the-counter Calcium burden
Calcium acetate 667–6000 mg 9 Swallowed tablet Less calcium than calcium carbonate Needs prescription
Lanthanum 500–3750 mg 3 Chewable and swallowed tablet (can be crushed) Lower pill burden than many other binders Expensive
Sevelamer 800–8000 mg 10 Swallowed tablet and granule packets Lowers low-density lipoprotein cholesterol High pill burden
Sucroferric oxyhydroxide 500–3000 mg 3.75 Chewable tablet Lower pill burden Cost and gastrointestinal side effects
Ferric citrate 210–2500 mg 9 Swallowed tablet Improves iron parameters Expensive
PBED = phosphorus binder equivalent dose.
Information from Cleveland Clinic Journal of Medicine August 2018, 85 (8) 629-638; DOI: https://doi.org/10.3949/ccjm.85a.17054

Expect sevelamer (Renagel) or lanthanum (Fosrenol) to be saved for patients with hypercalcemia. Generally continue binders during a hospital stay for patients who are eating. Verify binders are scheduled with meals, not just "TID (Three Times a Day)". Switch to a formulary binder if needed. But check calcium before using a calcium-based binder. Assess individual calcium and phosphorus levels rather than calculating a calcium-phosphate product.

If tube feeds are started, work with the dietician or NUTRITIONIST to try a low-phosphorus formula and consider temporarily stopping the binder (see Table 2). But if phosphate levels continue to rise, consider restarting the binder. Check whether you can crush it first and evaluate frequency. For example, switch sevelamer tabs (Renagel) to suspension since tabs can clog the tube. Consider scheduling as often as every 4 hours with tube feeding, if needed. Keep in mind to temporarily stop binders during continuous renal replacement therapy (CRRT), it often leads to hypophosphatemia.

Table (2). Phosphate content of foods
Type Food
High phosphate-to-protein ratio (avoid in end-stage kidney disease) Egg yolk
Beans, lentils, and dried peas
Cheese
Milk
Nuts and seeds
Organ meats and certain seafoods like shrimp, crab, and oysters
Low phosphate-to-protein ratio Egg white
White bread, pasta, crackers
Soups that are water-based or broth-based
Seafoods like sea bass
Information from Cleveland Clinic Journal of Medicine August 2018, 85 (8) 629-638; DOI: https://doi.org/10.3949/ccjm.85a.17054

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