| In vivo | Conivaptan administered intravenously at doses of 0.03, 0.1, and 0.3 mg/kg increases urine volume and decreases urine osmolality in a dose-dependent manner in both myocardial infarction and sham-operated rats. In myocardial infarction rats, a dose of 0.3 mg/kg notably lowers right ventricular systolic pressure, left ventricular end-diastolic pressure, reduces lung/body weight ratio, and right atrial pressure, while significantly enhancing dP/dt(max)/left ventricular pressure. Additionally, conivaptan acutely augments urine volume, reduces osmolality, and at study conclusion, cirrhotic rats treated with the V(1a)/V(2)-AVP receptor antagonist exhibit neither hyponatremia nor hypoosmolality. It also normalizes sodium urine volume without impacting creatinine clearance or arterial pressure. At dosages ranging from 0.01 to 0.1 mg/kg i.v., conivaptan demonstrates a dose-dependent diuretic effect in dogs, effectively inhibits vasopressin-induced pressor effects, and at 0.1 mg/kg, substantially blocks vasoconstriction from exogenous vasopressin. Furthermore, at 0.1 mg/kg i.v., it significantly enhances cardiac function in dogs with congestive heart failure as demonstrated by increases in left ventricular dP/dtmax, cardiac output, and stroke volume, alongside significant reductions in left ventricular end-diastolic pressure and total peripheral vascular resistance. |
United States
