Hernodynamic Effects of Prenalterol, a β1‐Adrenoreceptor Agonist, in Hypotension Induced by High Thoracic Epidural Block in Man

The hemodynamic effects of prenalterol, a new β1-adrenoreceptor agonist, on hypotension induced by a thoracic epidural block extending between TI and TI2 and thereby blorking 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 β1 agonist with a marked inotropic but no chronotropic property.