Where vaptans do and do not fit in the treatment of hyponatremia.

The treatment of hyponatremia, an exceedingly common electrolyte disorder, has been a subject of controversy for many years. The advent of vasopressin antagonists (vaptans) has added to the treatment arsenal. This review focuses on why hyponatremia should be treated and the role of these antagonists in the treatment. Upon analysis of the available literature, we conclude that there is presently no role for vaptans in acute symptomatic hyponatremia. Although numerous therapeutic approaches are available for chronic symptomatic hyponatremia, vasopressin antagonists provide a simpler treatment option. Vaptans are efficacious in raising serum sodium in long-standing 'asymptomatic' hyponatremia. However, the cost of the only Food and Drug Administration-approved oral agent (tolvaptan) makes its use prohibitive for most patients in this setting.