Isoproterenol in offsetting adverse effects of vasopressin in cirrhotic patients.

Vasopressin administered as a peripheral infusion (40 U/hr) significantly reduced portal vein pressure in ten awake patients with cirrhosis and portal hypertension. A vasopressin-induced reduction in cardiac output occurred in five of the ten patients (50 per cent). Vasopressin-induced changes in systemic arterial pressure, heart rate, and portal venous pressure were independent of alterations in cardiac output. When the five patients with vasopressin-induced reductions in cardiac output were given a combination of vasopressin and isoproterenol, cardiac output was maintained and the reduction in portal vein pressure was equal to that observed with unopposed vasopressin therapy. Thus, the addition of isoproterenol prevented a vasopressin-induced reduction in cardiac output while permitting vasopressin to reduce portal vein pressure.