Conivaptan HCl is primarily used in the management of euvolemic and hypervolemic hyponatremia, conditions characterized by low sodium levels in the blood with normal or excess fluid volume, respectively. It is effective in treating hyponatremia associated with conditions such as syndrome of inappropriate antidiuretic hormone secretion (SIADH), congestive heart failure, or cirrhosis. The drug works by acting as a dual vasopressin receptor antagonist, inhibiting the action of vasopressin on V1A and V2 receptors in the kidneys and vascular smooth muscle. This inhibition reduces water reabsorption in the renal tubules and promotes aquaresis, leading to increased free water excretion and a gradual correction of sodium levels. It is administered intravenously in a hospital setting, allowing for careful monitoring of electrolyte balance and fluid status. Conivaptan HCl is especially valuable in cases where rapid correction of hyponatremia is necessary to prevent neurological complications. However, its use requires caution to avoid overly rapid sodium correction, which can lead to osmotic demyelination syndrome.