Renagel is a polymeric amine that binds phosphate in the gastrointestinal tract and prevents phosphate from being absorbed.
Renagel is specifically indicated for the control of serum phosphorus in patients with chronic kidney disease on dialysis.
Renagel is supplied as 400 mg and 800 mg tablets designed for oral administration. The recommended initial dose is as follows:
Patients Not Taking a Phosphate Binder
Renagel 800 to 1600 mg, which can be administered as one or two 800 mg tablets or two to four 400 mg tablets, with meals based on serum phosphorus level:
Serum Phosphorus >5.5 and <7.5 mg/dL: Renagel 800 mg: 1 tablet three times daily with meals; Renagel 400 mg: 2 tablets three times daily with meals
Serum Phosphorus ≥ 7.5 and <9.0 mg/dL: Renagel 800 mg: 2 tablets three times daily with meals; Renagel 400 mg: 3 tablets three times daily with meals
Serum Phosphorus ≥9.0 mg/dL: Renagel 800 mg: 2 tablets three times daily with meals; Renagel 400 mg: 4 tablets three times daily with meals
Patients Switching From Calcium Acetate
Calcium Acetate 667 mg (Tablets per meal)
1 tablet: Renagel 800 mg: 1 tablet/meal; Renagel 400 mg: 2 tablets/meal
2 tablets: Renagel 800 mg: 2 tablets/meal; Renagel 400 mg: 3 tablets/meal
3 tablets Renagel 800 mg: 3 tablets/meal; Renagel 400 mg: 5 tablets/meal.
Dose Titration for All Patients Taking Renagel Dosage should be adjusted based on the serum phosphorus concentration with a goal of lowering serum phosphorus to 5.5 mg/dL or less.
Serum Phosphorus >5.5 mg/dL: increase 1 tablet per meal at 2 week intervals
Serum Phosphorus 3.5 - 5.5 mg/dL: maintain current dose
Serum Phosphorus < 3.5 mg/dL: decrease 1 tablet per meal
The FDA approval of Renagel was based on six clinical trials: one double-blind placebo controlled 2-week study; two open-label uncontrolled 8-week studies and three active-controlled open-label studies with treatment durations of 8 to 52 weeks. Three of the active-controlled studies are described:
Active-Control, Crossover Study in Hemodialysis Patients
This trial enrolled 84 subjects on hemodialysis who were hyperphosphatemic (serum phosphorus > 6.0 mg/dL). Following a two-week phosphate binder washout period, subjects were randomized to receive Renagel and active control for eight weeks each. Treatment periods were separated by a two-week phosphate binder washout period. Subjects started on treatment three times per day with meals. Over each eight-week treatment period, at three separate time points the dose of Renagel could be titrated up 1 capsule or tablet per meal (3 per day) to control serum phosphorus, the dose of active control could also be altered to attain phosphate control. Both treatments significantly decreased mean serum phosphorus by about 2 mg/dL.
Active-Control, Parallel Study in Hemodialysis Patients
This trial enrolled 200 CKD patients on hemodialysis who were hyperphosphatemic (serum phosphorus > 5.5 mg/dL). Following a two-week phosphate binder washout period, subjects were randomized to receive Renagel 800 mg tablets or an active control. The two treatments produced similar decreases in serum phosphorus. At week 52, using last- observation-carried-forward, Renagel and control both significantly decreased mean serum phosphorus.
Active-Control, Parallel Study in Peritoneal Dialysis Patients
This trial enrolled 143 subjects on peritoneal dialysis who were hyperphosphatemic (serum phosphorus > 5.5 mg/dL). Following a two-week phosphate binder washout period, subjects were randomized to receive Renagel or active control open label for 12 weeks. Average daily Renagel dose at the end of treatment was 5.9 g (range 0.8 to 14.3 g). There were statistically significant changes in serum phosphorus (p < 0.001) for Renagel (-1.6 mg/dL from baseline of 7.5 mg/dL), similar to the active control.
Adverse events associated with the use of Renagel may include, but are not limited to, the following:
Renagel (sevelamer hydrochloride) is a non-absorbed binding crosslinked polymer. It contains multiple amines separated by one carbon from the polymer backbone. These amines exist in a protonated form in the intestine and interact with phosphate molecules through ionic and hydrogen bonding. By binding phosphate in the dietary tract and decreasing absorption, sevelamer hydrochloride lowers the phosphate concentration in the serum.
Burke SK, Slatopolsky EA, Goldberg DI RenaGel, a novel calcium- and aluminium-free phosphate binder, inhibits phosphate absorption in normal volunteers. Nephrology, Dialysis, Transplantation : Official Publication of the European Dialysis and Transplant Association - European Renal Association 1997 Aug;12(8):1640-4
Slatopolsky EA, Burke SK, Dillon MA RenaGel, a nonabsorbed calcium- and aluminum-free phosphate binder, lowers serum phosphorus and parathyroid hormone. The RenaGel Study Group. Kidney International 1999 Jan;55(1):299-307
Ramos R, Moreso F, Borras M, Ponz E, Buades JM, Teixidó J, Morey A, Garcia C, Vera M, Doñate MT, de Arellano MR, Barbosa F, González MT Sevelamer hydrochloride in peritoneal dialysis patients: results of a multicenter cross-sectional study. Peritoneal Dialysis International : Journal of the International Society for Peritoneal Dialysis 2007 Nov-Dec;27(6):697-701
Goldberg DI, Dillon MA, Slatopolsky EA, Garrett B, Gray JR, Marbury T, Weinberg M, Wombolt D, Burke SK Effect of RenaGel, a non-absorbed, calcium- and aluminium-free phosphate binder, on serum phosphorus, calcium, and intact parathyroid hormone in end-stage renal disease patients. Nephrology, Dialysis, Transplantation : Official Publication of the European Dialysis and Transplant Association - European Renal Association 1998 Sep;13(9):2303-10
For additional information regarding Renagel or serum phosphorus control in patients with chronic kidney disease on dialysis, please visit the Renagel web page.