Sevelamer carbonate (Renvela – Genzyme), a buffered form of the anion-exchange resin sevelamer hydrochloride (Renagel – Genzyme),1 has been approved by the FDA for use in patients with chronic kidney disease on dialysis. According to the manufacturer, Renvela will replace Renagel, which has been shown to induce or exacerbate metabolic acidosis in patients on dialysis. Two randomized, crossover studies found the two sevelamer salts equivalent in their ability to lower serum phosphate.2,3 Patients taking the carbonate had higher serum bicarbonate concentrations and fewer gastrointestinal adverse effects. Sevelamer carbonate, which is available in 800-mg tablets, can be substituted for the hydrochloride salt gram for gram. Recent studies in patients beginning hemodialysis have suggested a possible mortality benefit for sevelamer compared to less expensive calcium- based phosphate binders,4,5 but some critics are skeptical.6
3. S Fan et al. Renvela (sevelamer carbonate) powder and Renagel (sevelamer hydrochloride) tablets: report of a randomized, cross-over study in chronic kidney disease (CKD) patients on hemodialysis (poster). American Society of Nephrology Renal Week. October 31- November 5 2007. San Francisco.