[{"from": "human", "value": "Provide a description of this molecule. [C][C][=C][C][=C][C][=C][Ring1][=Branch1][C][=Branch1][C][=O][N][C][=C][C][=Branch2][Ring1][P][=C][Branch1][Branch1][C][=C][Ring1][=Branch1][C][=Branch1][C][=O][N][C][C][C][C][Branch1][=C][C][=C][Ring1][#Branch1][C][=C][C][=Branch1][Ring2][=C][Ring1][=Branch1][Cl][O][C]"}, {"from": "gpt", "value": "The molecule is an orally bioavailable, selective, arginine vasopressin receptor 2 (V2, AVPR2) antagonist that can be used to treat hyponatremia. Upon oral administration, tolvaptan selectively and competitively binds to and blocks the V2 receptor located in the walls of the vasculature and luminal membranes of renal collecting ducts, thereby preventing the binding of vasopressin to the V2 receptor. This prevents water absorption in the kidneys and increases the excretion of electrolyte-free water via the kidneys. This reduces intravascular volume and increases serum sodium concentrations and osmolality."}]