[Vasopressin receptor antagonists and heart failure].

Vasopressin plays a physiological role in regulation of blood pressure, fluid volume, and serum osmolality. In heart failure inadequate release of vasopressin may result in excess fluid retention and hyponatremia. Vasopressin receptor antagonists are a new class of orally active drugs targeted to inhibit one or more of three distinct vasopressin receptors, namely V1a- (-->vasoconstriction), V1b- (-->release of ACTH) und V2-receptors (-->inhibition of free water reabsorption in the kidney). In cardiac decompensation with fluid overload selective V2- (Lixivaptan, satavaptan and tolvaptan) and non-selective V1a/V2-receptor blockers (Conivaptan) have been shown to be superior to standard therapy, as they allow for a faster weight loss and a more rapid symptomatic improvement (i.e. reduction in dyspnea). Inhibiting free water reabsorption without affecting renal sodium excretion vasopressin receptor antagonists allow for a controlled normalisation of serum natrium in euvolemic and hypervolemic hyponatremia. Vasopressin antagonists are well tolerated and have--in contrast to diuretics--no negative influence on renal function and serum potassium. Heart rate and blood pressure are not affected by vasopressin receptor antagonists. However, despite its excellent acute clinical effects long-term treatment with tolvaptan did not result in a reduced mortality and morbidity in heart failure patients over a mean follow-up of 9.9 months in the EVEREST trial.