As expected, copeptin plasma concentrations increased in the tolvaptan group. Cystatin C decreased in the tolvaptanTable 2 Renal endpoints comparisongroup, with median change in concentrations being signifi- cantly different than furosemide at 24 h, but the difference was lost at 96 h. There was high variability in other plasma and urinary biomarkers measured. As a consequence, there were no detectable differences between tolvaptan and furo- semide groups in NT-proBNP, PRA, or urinary NGAL:Scr con- centrations at any time point.