Therapeutic role of vasopressin receptor antagonism in patients with liver cirrhosis.

Vasopressin, or antidiuretic hormone, is a peptide hormone that is released from the posterior pituitary gland in response to changes in blood pressure and plasma osmolality. The main pathophysiological states associated with high plasma vasopressin concentrations are cirrhosis, cardiac failure and syndrome of inappropriate antidiuretic hormone (SIADH) secretion. Pharmacological treatments for disorders of excess vasopressin secretion have been limited. However, oral bio-available selective and non-selective V(1) and V(2) receptor antagonists have recently become available for clinical use. Water retention in cirrhosis is a common problem, leading to ascites, peripheral oedema and hyponatraemia. Raised plasma vasopressin concentrations and decreased delivery of glomerular filtrate are believed to be the most important factors in the development of water retention. V(2) receptor antagonists are aquaretic agents that promote water excretion and improve hyponatraemia. Their potential role in cirrhosis has been examined in a number of recent studies that have shown increased free water clearance and serum sodium concentrations with few adverse effects. V(2) receptor antagonists represent a novel and promising new class of agent that may have major clinical utility in the treatment of patients with liver cirrhosis.