Sevelamer

Sevelamer is a non-calcium, non-metal phosphate binder used to treat hyperphosphatemia in patients with chronic kidney disease on dialysis. It exists as sevelamer hydrochloride (Renagel) and sevelamer carbonate (Renvela). The active polymer binds phosphate in the gastrointestinal tract, forming insoluble complexes excreted in feces. This reduces intestinal phosphate absorption and lowers serum phosphate and the calcium-phosphate product without increasing calcium load. Sevelamer carbonate may modestly reduce LDL cholesterol by interfering with bile-acid reabsorption.

Administration and dosing are individualized; sevelamer is taken with meals as tablets or powder. The hydrochloride form can contribute a chloride load and metabolic acidosis, whereas the carbonate form has less acid load. The medication is not absorbed systemically.

Side effects and warnings include gastrointestinal symptoms such as nausea, vomiting, diarrhea, constipation, and dyspepsia; rare but serious risks include intestinal obstruction. There is a potential for reduced absorption of fat-soluble vitamins and other orally administered drugs; other medications or vitamins should be taken either 1-2 hours before or 3-6 hours after sevelamer. Esophageal obstruction has been reported with large tablets; caution is advised in patients with swallowing disorders.

Pregnancy and lactation data are limited; sevelamer should be used only if the potential benefit justifies the potential risk. Overall, sevelamer is generally well tolerated and offers an alternative to calcium- or metal-based phosphate binders in CKD-related hyperphosphatemia.