Arginine vasopressin receptor antagonists (vaptans): Pharmacological tools and potential therapeutic agents

The development of various non-peptide vasopressin receptor antagonists presents a new area of drug discovery for the treatment of heart failure and hyponatremia of multiple causes. Arginine vasopressin (AVP) attracted attention as a potentially important neurohormonal mediator of the heart failure (HF) syndrome and hyponatremic states in humans because AVP influences renal handling of free water, vasoconstriction and myocyte biology through activation of V₂ and V_1a receptors. Current research is exploring V₂- and dual V_1a/V₂ receptor antagonism for the treatment of hyponatremia, as well as for the congestion and edema associated with chronic HF, because vasopressin receptor antagonists might offer benefits in comparison with conventional loop diuretics. The purpose of this review is to update the current status of experimental and clinical studies with available vasopressin receptor antagonists (conivaptan and tolvaptan) and their potential role in the treatment of HF and hyponatremia of multiple causes.