Otsuka Pharmaceutical Co., Ltd. (Otsuka) announces that a V₂ -receptor antagonist for the treatment of cardiac edema, SAMTASU^® 8 mg and 16 mg Intravenous Infusion, has been launched in Japan on May 30, 2022.

SAMTASU is a prodrug of oral tolvaptan (generic name is tolvaptan sodium phosphate). A prodrug is a medication that is converted into an active drug in the human body following administration. Tolvaptan, discovered by Otsuka, is a novel compound that is as an antagonist of the vasopressin V₂-receptor. It inhibits water reabsorption at the renal collecting duct, thereby enhancing water diuresis (aquaresis) without depletion of electrolytes. Until now, tolvaptan has been available only in oral form.

SAMTASU is an intravenous diuretic that provides a new treatment option for patients with fluid retention who have difficulty receiving tolvaptan orally.