Phosphate binder

Phosphate binders are medications used to reduce the absorption of phosphate and taken with meals and snacks. They are typically used in people with chronic kidney failure (CKF) as they often have difficulty getting rid of the phosphates that get into their blood (i.e., the serum phosphate in chronic kidney failure is typically elevated).

Medical use

For people with chronic kidney failure, controlling serum phosphate is important because it is associated with bone pathology and regulated together with serum calcium by the parathyroid hormone (PTH).

Adverse effects

With regard to phosphate binders, aluminium-containing compounds (such as aluminium hydroxide) are the least preferred because prolonged aluminium intake can cause encephalopathy and osteomalacia. If calcium is already being used as a supplement, additional calcium used as a phosphate binder may cause hypercalcemia and tissue-damaging calcinosis. One may avoid these adverse effects by using phosphate binders that do not contain calcium or aluminium as active ingredients, such as lanthanum carbonate or sevelamer.

Choice of agent

There have been limited trials comparing phosphate binders to placebo in the treatment of hyperphosphatemia in people with chronic kidney disease. When compared with people receiving calcium-based binders, people taking sevelamer have a reduced all-cause mortality.^[1]

Types

Summary of Common Oral Phosphate Binders^[2]

Phosphate Binder	Brands	Advantages	Disadvantages
Aluminum salts	Alucaps	Calcium free	Risk of aluminum toxicity
	Basaljel	High binder efficiency regardless of pH	Requires frequent monitoring-extra cost
		Cheap
		Moderate tablet burden
Calcium carbonate	Calcichew	Aluminum free	Calcium containing-potential risk of hypercalcemia and ectopic calcification
	Titralac	Moderate binding efficacy	Parathyroid hormone oversuppression
		Relatively low cost	Gastrointestinal side effects
		Moderate tablet burden	Efficacy pH dependent
		Chewable
Calcium acetate	Lenal Ace	Aluminum free	Calcium containing-potential risk of hypercalcemia and ectopic calcification
	PhosLo	Higher efficacy than calcichew/sevelamer	Parathyroid hormone oversuppression
		Moderately cheap	Gastrointestinal side effects
		Lower calcium load than calcium carbonate	Large tablets, nonchewable formulation
Sevelamer hydrochloride/Sevelamer carbonate	Renagel	Aluminium and calcium free	Relatively costly
	Renvela	No gastrointestinal absorption	High pill burden
		Moderate efficacy	Large tablets, nonchewable formulation
		Reduces total and low-density lipoprotein cholesterol	Gastrointestinal side effects
			Binds fat-soluble vitamins
Lanthanum carbonate	Fosrenol	Aluminum and calcium free	Relatively costly
		Minimal gastrointestinal absorption	Gastrointestinal side effects
		High efficacy across full pH range
		Chewable formulation
		Palatable
		Low tablet burden

• Calcium acetate/magnesium carbonate

Mechanism of action

These agents work by binding to phosphate in the GI tract, thereby making it unavailable to the body for absorption. Hence, these drugs are usually taken with meals to bind any phosphate that may be present in the ingested food. Phosphate binders may be simple molecular entities (such as magnesium, aluminium, calcium, or lanthanum salts) that react with phosphate and form an insoluble compound. Phosphate binders such as sevelamer may also be polymeric structures which bind to phosphate and are then excreted.

References

1. Patel, L; Bernard, LM; Elder, GJ (14 December 2015). "Sevelamer versus calcium-based binders for treatment of hyperphosphatemia in CKD: a meta-analysis of randomized controlled trials.". Clinical Journal of the American Society of Nephrology. 11 (2): 232–244. doi:10.2215/CJN.06800615. PMID 26668024.
2. Burtis, C.A.; Ashwood, E.R. and Bruns, D.E. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 5th Edition. Elsevier. pp1552

1. ^ Lederer E, Ouseph R, Erbeck K. Hyperphosphatemia, eMedicine.com, URL: http://www.emedicine.com/med/topic1097.htm, Accessed on July 14, 2005.
2. ^ Spiegel, David M.; Farmer, Beverly; Smits, Gerard; Chonchol, Michel (2007). "Magnesium Carbonate is an Effective Phosphate Binder for Chronic Hemodialysis Patients: A Pilot Study". Journal of Renal Nutrition. 17 (6): 416. doi:10.1053/j.jrn.2007.08.005. PMID 17971314.

External links

• High Phosphate Control - Official Fosrenol Homepage*
• Phosphate Binders: What Are They And How Do They Work? - American Association of Kidney Patients*
• Phosphate Binders - National Kidney Foundation
• Phosphate Binders - Northwest Kidney Centers - a center that provides services for people with ESRD in the Seattle area.
• High Phosphate - Phosphorus Control - Information for healthcare professionals on the treatment and management of hyperphosphatemia

Common Phosphate Binders

• Hutchison, A. J.; Wilkie, M. (2012). "Use of magnesium as a drug in chronic kidney disease". Clinical Kidney Journal. 5: i62. doi:10.1093/ndtplus/sfr168.
• Lanthanum - medlineplus.org
• Sevelamer - medlineplus.org
• Sevelamer - Renvela.com