Tolvaptan Efficiently Reduces Intracellular Fluid: Working Toward a Potential Treatment Option for Cellular Edema

Objective Tolvaptan is a class of diuretics that reduce body water through aquaresis. One of the most prominent characteristics of these agents is that worsening of the renal function is less likely to occur. We investigated the underlying mechanism concerning the change in the intracellular fluid (ICF) when the body fluid is reduced. Methods In this retrospective observational study, five overhydrated chronic kidney disease (CKD) patients with edema or pleural effusion treated with tolvaptan were assessed by the bioelectrical impedance method twice: once before and once after tolvaptan therapy. The changes in the ICF rate were compared with those in 11 hemodialysis patients undergoing body fluid reduction by hemodialysis. Results Removal of the body fluid either by tolvaptan or by hemodialysis increased the post/pre-ratio of ICW/total body water (TBW). Tolvaptan reduced the ICF more efficiently than hemodialysis. Conclusion Tolvaptan treatment lessens body fluid by the efficient reduction of the ICF.