The effects of a combination of vasopressin and a calcium channel blocker (nicardipine) on portohepatic hemodynamics and liver function were compared with the effects of vasopressin alone in 18 patients with portal hypertension. Nine patients received 0.4 units/min of vasopressin and 9 patients received the same dose of vasopressin plus 0.3 mg/min of nicardipine for 40 min. Vasopressin plus nicardipine induced a significant reduction in both free portal venous pressure and the portal venous pressure gradient. These effects were similar to the changes with vasopressin alone (-14% vs. -16% in free portal venous pressure; -29% vs. -31% in portal venous pressure gradient). Vasopressin decreased both hepatic blood flow (-34%, P < 0.01) and intrinsic clearance of indocyanine green (-22%, P < 0.05). In contrast, these two parameters did not significantly change after vasopressin plus nicardipine (-8% and -3%, respectively). These results suggest that the addition of nicardipine improves hepatic impairment induced by vasopressin but causes no further reduction on portal pressure.