Thus, recent limited regulatory approval of the vasopressin antagonists mozavaptan in Japan (oral OPC-31260, for paraneoplastic SIADH [Physuline, Otsuka Pharmaceutical]) and conivaptan in the United States (parenteral formulation, for hospitalized patients with euvolemic SIADH [Vaprisol, Astellas Pharma]) are promising for the management of hyponatremia