Optimal treatment of hyponatremia in clinical practice

V Burst, M Witthus, F Grundmann, R-U Muller, T Kubacki

Hyponatremia is the most common electrolyte disorder and can lead to a wide spectrum of symptoms, from apparently asymptomatic to life-threatening. Severe symptoms are usually a consequence of cerebral edema and should prompt immediate treatment with hypertonic fluid. In less severe cases, or after resolution of severe symptoms thorough clinical examination of volume status, additional laboratory tests are needed in order to identify the underlying cause and to classify the hyponatremia as hypo-, eu- or hyper-volemic. Although most cases of hyponatremia are attributed to an excessive action of antidiuretic hormone (vasopressin), optimal therapy regimes differ. While hypovolemic hyponatremia is treated appropriately with the administration of isotonic saline, eu- and hyper-volemic hyponatremia are classically treated with fluid restriction. In recent years a new class of drugs, vasopressin receptor-2 antagonists, called vaptans, have emerged as a potent and safe choice for the treatment of fluid restriction-resistant nonsevere hyponatremia.