The Use of Vaptans in Hyponatraemia

Hyponatraemia is the most common electrolyte disorder in clinical practice. It is associated with increased morbidity, mortality, and length of hospital stay, and therefore represents a clinical, economic, and social burden for healthcare costs and caregivers. Acute and severe hyponatraemia is associated with severe neurological alterations that may lead to cerebral oedema and death. Even mild chronic hyponatraemia has been associated with neurological and extraneurological disorders, such as gait disturbances, attention deficit, increased risk of bone loss, falls, and fractures. These aspects appear relevant particularly in the elderly. Furthermore, an overly rapid correction of hyponatraemia may cause osmotic demyelination, thus making it necessary to define safe treatment strategies. In the last few years, the availability of new drugs, i.e. the vasopressin receptor antagonists or vaptans, has improved the therapeutic choices for the treatment of hyponatraemia. This review summarises the main aspects regarding the use of these drugs, in particular tolvaptan and conivaptan, which are the only vaptans currently available in clinical practice.