OBJECTIVETo evaluate the efficacy and safety of tolvaptan on treating congestive heart failure patients with hyponatremia.

METHODSThis randomized double-blind placebo-controlled multicenter trial enrolled 65 patients with congestive heart failure and hyponatremia. On top of standard therapy, patients were randomized to receive either tolvaptan 15 - 60 mg daily or placebo according to the serum sodium concentration. The primary end points were the change of average daily serum sodium concentration from baseline to day 4 and to day 7 respectively. Patients' weight, urine volume, sign of heart failure, heart function, blood pressure, heart rate, and all adverse events were observed.

RESULTSThe daily serum sodium concentration increase was significantly higher in tolvaptan group than in placebo group during the first 4 days [(5.6 ± 3.5) mmol/L vs. (2.5 ± 3.4) mmol/L, P < 0.05] and 7 days [(5.9 ± 3.5) mmol/L vs. (2.8 ± 3.3) mmol/L, P < 0.05]. Moreover, urine volume increase and body weight decrease were more significant in tolvaptan group than in placebo group (all P < 0.05). The change of sign of heart failure, heart function, blood pressure and heart rate was similar between two groups (P > 0.05). There were more drug related adverse events of thirst (11.4%) and hypernatremia (5.7%) in Tolvaptan group. One patient in tolvaptan group developed agranulocytosis during therapy period and recovered post therapy.

CONCLUSIONSTolvaptan could effectively increase serum sodium concentration, urine volume, and improve liquid balance in heart failure patients with hyponatremia. Tolvaptan related serious adverse event was low and could be well tolerated by patients tested in this cohort.