Vasopressin antagonists are drugs that bind to vasopressin receptors (V1A, V1B and V2) and block the action of vasopressin (antidiuretic hormone, ADH), which is a hormone released by the pituitary gland. Vasopressin causes vasoconstriction and increases reabsorption of water by the kidneys.
V1A and V2 receptors are found peripherally and V1A and V1B receptors are found in the central nervous system. V1A receptors regulate blood pressure and V2 receptors have an effect on renal function.
Vasopressin antagonists are used to treat hyponatremia particularly in congestive heart failure patients.