Hyponatremia

Hyponatremia is defined as sodium concentration in serum less than 135 mEq/L.
Its basically an electrolyte abnormality caused by an excess of total body water compared to total body sodium content. Symptomatic hyponatremia can accompany heart failure, syndrome of inappropriate antidiuretic hormone secretion (SIADH) and liver cirrhosis. Tolvaptan is the first orally active, specific vasopressin 2 antagonist to be licensed for use in humans.