The drug sevelamer, often referred to as a phosphate binder, is a medication that helps to decrease the concentration of phosphate in the blood. It is used to treat patients with hyperphosphatemia, which is a condition marked by high serum phosphate levels. People with chronic kidney failure represent the largest group of patients that have problems with high phosphorus levels in their bodies, since the kidneys are the organs of the body that excrete phosphorus.
An important use of sevelamer is to decrease the concentration of phosphate in the blood. Phosphate is a mineral that has a critical role in the body, as it is an important constituent of bone, is part of different proteins important for the proper function of the body, and serves as an electrolyte in the blood. Although the concentration of phosphate within the blood is carefully regulated by the body's endocrine system, in some pathologic conditions the levels of phosphate in the blood can rise to dangerous levels. Sevelamer can help to decrease the concentration of this mineral by binding to it in the gastrointestinal tract and preventing its absorption into the bloodstream. It can do this because it is a large molecule with many positive charges, and can form a chemical bond with the negatively charged phosphate.
Sevelamer is most commonly used in patients with chronic kidney failure, and in particular is used for patients being treated with dialysis, a therapeutic measure that filters the blood artificially and replaces some of the function of the kidney. In healthy patients, the kidneys filter the blood and rid the body of excess phosphate by excreting it into the urine. People with dysfunction of their kidneys cannot dispose of their phosphate properly, and therefore accumulate high levels of phosphate in the blood.
Not all patients with kidney failure need to take sevelamer. It is often prescribed in patients with end-stage renal disease who have serum phosphate levels greater than 5.5 milligrams per deciliter. Often the dose of the medication is increased slowly over time until the body attains a serum phosphate level between 3.5 to 5.5.
According to the United States Federal Drug Administration (FDA), the only approved use of sevelamer is to treat high blood phosphate levels in patients with chronic kidney failure. Some researchers, however, have considered using the medication to treat high blood cholesterol levels. Others have suggested that elevated phosphate levels in otherwise healthy patients could be a risk factor for heart disease, and recommend taking interventions to lower phosphorus levels in the blood as much as possible.
