While a number of orally active non-peptide << V(2) >> antagonists (Vaptans); notably, Tolvaptan, [[ Lixivaptan ]] and Satavaptan, are currently in Phase III clinical trials; to date, only the mixed V(2)/V(1a), antagonist Conivaptan (Vaprisol), has been approved by the US FDA for clinical use (by i.v. administration), for the treatment of euvolemic and hypervolemic hyponatremia in hospitalized patients.