Preliminary Report of Intravenous Tolvaptan Sodium Phosphate (Samtas®) Treatment in Decompensated Heart Failure

Background: Tolvaptan sodium phosphate (Samtas (R); Otsuka Pharmaceutical, Tokyo, Japan) is a novel intravenous aquaretic diuretic aimed at individuals experiencing advanced congestion refractory to conventional diuretics and having difficulty with oral intake. Despite its potential, the true efficacy and practicality of this compound within real-world clinical settings remain obscure. Methods: A retrospective analysis of clinical data was conducted, examining trends among consecutive in-hospital patients diagnosed with congestive heart failure who underwent treatment with tolvaptan sodium phosphate at a prominent academic medical center between June 2022 and June 2023. Results: Twenty-one patients were enrolled (median age: 75 years, serum N-terminal pro B-type natriuretic peptide: 8941 pg/mL). Among them, 14 patients (67%) received non-invasive/invasive positive-pressure ventilation, and 17 patients (81%) concurrently received intravenous inotropes. Subsequent to the initiation of tolvaptan sodium phosphate treatment, a significant increase in urine volume was observed on the following day (p = 0.036). Urine osmolality decreased from 356 (318, 443) at baseline to 247 (176, 333) mOsm/kg after 4 h (p = 0.002). No occurrences of hypernatremia were recorded during the therapeutic period. Notably, two patients transitioned from tolvaptan sodium phosphate treatment to continuous hemodiafiltration due to insufficient efficacy. Conclusions: In routine clinical practice, intravenous tolvaptan sodium phosphate exhibits potential efficacy and practicability in the majority of congestive heart failure patients exhibiting refractory congestion, unstable hemodynamics, and challenges with oral intake.