Hemodynamic effects of prenalterol, a beta1-adrenoreceptor agonist, in hypotension induced by high thoracic epidural block in man.

The hemodynamic effects of prenalterol, a new beta1-adrenoreceptor agonist, on hypotension induced by a thoracic epidural block extending between T1 and T12 and thereby blocking the cardiac sympathetic supply have been studied in eight patients scheduled for abdominal aortic aneurysm resection. The thoracic epidural block induced a drop in blood pressure, due to a reduction in cardiac output and systemic vascular resistance. Intravenous infusion of 10 mg of prenalterol rapidly and effectively reversed the hypotension by an increase in cardiac output without any effects on systemic vascular resistance or heart rate. The results indicate that prenalterol is a pure beta1 agonist with a marked inotropic but no chronotropic property.