Sevelamer is a medication used to treat high levels of phosphate in the blood, a condition known as hyperphosphatemia, which commonly occurs in patients with chronic kidney disease (CKD) who are on dialysis. It belongs to a class of drugs called phosphate binders. Sevelamer works by binding to phosphate in the intestine, preventing its absorption into the bloodstream. By reducing phosphate levels in the blood, sevelamer helps to prevent complications associated with hyperphosphatemia, such as bone disease and cardiovascular problems.