Sevelamer hydrochloride (Renagel (R)), a nonabsorbed phosphate-binding polymer, does not interfere with digoxin or warfarin pharmacokinetics

Sevelamer hydrochloride (Renagel(R)) is a nonabsorbed phosphate-binding pol ymer marketed for the treatment of hyperphosphatemia in adult patients rece iving hemodialysis. Sevelamer also exhibits bile acid-binding properties re sulting in LDL cholesterol lowering. Potential drug interactions between di goxin and warfarin and sevelamer were studied. These two drugs were chosen because they are known to bind to the bile acid-binding polymers, cholestyr amine and colestipol. Studies were single dose, crossover, with or without six 2.4 g doses of sevelamer. Plasma concentrations were determined using v alidated analytical methods. The pharmacokinetic profiles of digoxin and wa rfarin were not altered by the simultaneous and continued administration of sevelamer. Values for the ratio of ln[AUC((0-infinity))], ln[AUC((0-t))] a nd ln[C-max] with and without sevelamer were close to 100%, and the 90% con fidence intervals for these ratios were within the 80% to 125% range. It wa s concluded that sevelamer does not interfere with the absorption or excret ion of digoxin or warfarin. (C) 2001 the American College of Clinical Pharm acology.