October 27, 2010 – Otsuka Pharmaceutical Co., Ltd. announced that the Japanese Ministry of Health, Labour and Welfare (MHLW) approved SAMSCA™ (nonproprietary name: tolvaptan), a vasopressin V2-receptor antagonist, for the treatment of excess water retention in patients with cardiac failure when the treatment by other diuretics including loop diuretics is ineffective.SAMSCA is a nonpeptide vasopressin V2-receptor antagonist discovered by Otsuka Pharmaceutical in 1991 with a unique mechanism of action that selectively blocks the binding of vasopressin to the V2-receptors in the collecting duct of the kidney. The binding of vasopressin with V2-receptors can cause water retention. By inhibiting the effects of vasopressin at the V2-receptor, SAMSCA increases the excretion of free water and reduces the re-absorption of water from urine into the blood without directly affecting the excretion of sodium and other electrolytes.
"Our research and development on vasopressin V2-receptor antagonists, that began in the early 1980s, was in response to requests from the medical profession for a diuretic that excretes only water," said Taro Iwamoto, Ph.D., President and Representative Director, Otsuka Pharmaceutical... Otsuka Pharmaceutical's Press Release -
