Clinical Experience of a New Inotropic Agent—Prenalterol—in—Hypotension and Heart Failure

The hemodynamic effects of a new cardioselective beta agonist, prenalterol, was evaluated in patients with hypotension secondary to thoracic sympathetic block induced by epidural anesthesia and in patients with low resistance distributive shock secondary to gram‐negative sepsis. The drug was also given to patients on chronic beta blockade suffering from hypotension and backward failure, to patients with acute hypotension developed after acute beta blockade, to one patient with acute myocardial infarction (AMI) and shock, and to one patient with shock due to amitriptyline intoxication. Ten milligrams of prenalterol rapidly reversed the fall in cardiac output and systolic blood pressure (SBP) after the sympathetic block in eight patients without affecting heart rate (HR) or systemic vascular resistance (SVR). In five patients with gram‐negative shock, 150 μg/kg prenalterol, after volume substitution to high normal range of pulmonary artery diastolic pressure (PADP), increased mean artery pressure from 56±13 to 86±16 and cardiac index from 2.4±0.3 to 3.9±0.71 with no change in SVR, HR, and PADP. In six patients i.v. prenalterol in doses of 5 30 mg successfully reversed the cardiodepressive effect of acute or chronic beta blockade. In two other cases of low output failure due to complicated AMI and overdose of amitriptyline, respectively, prenalterol was found to be of value also in patients with cardiogenic shock. The positive inotropic effect of prenalterol was achieved in these patients with good tolerance and without arrhythmogenic or other side effects.