Circulatory response to prenalterol in normal subjects and in patients with primary congestive cardiomyopathy.
Experimental pharmacology indicates that prenalterol is a selective beta 1-adrenoceptor activator. In 5 normal individuals, 15 minutes after the drug (infused at a dose of 15 micrograms/kg over 5 min) the following circulatory changes were seen: a) increase of cardiac index (+31%), heart rate, stroke index, systolic aortic pressure, left and right ventricular mean rate of ejection and mean rate of the pressure rise in either ventricle during the pre-ejection phase; b) reduction of systemic vascular resistance (-18%), appearance, built-up and disappearance times in the left ventricular dye dilution curves. Pulmonary systolic, diastolic and wedge pressures and vascular resistance did not vary consistently. The circulatory effects persisted almost unchanged 30 minutes after the infusion. In a group of 5 patients with heart failure due to primary congestive cardiomyopathy, refractory to conventional therapy, the haemodynamic response to prenalterol (infused at a dose of 30 micrograms/kg over 5 min) was qualitatively similar to that of normal subjects in 3 cases. In 2 other patients cardiac performance deteriorated. The reasons for this paradoxical effect were not identified. These preliminary results suggest that prenalterol is a potent selective inotropic agent in man, that may assist in the therapeutic management of refractory heart failure due to congestive cardiomyopathy. However, careful haemodynamic monitoring is advisable for its use in this dysfunction until broader clinical experience can be accumulated.
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000328:Adult; D001775:Blood Circulation / Q000187:drug effects*; D001794:Blood Pressure / Q000187:drug effects; D006328:Cardiac Catheterization; D002302:Cardiac Output / Q000187:drug effects; D009202:Cardiomyopathies / Q000188:drug therapy*; D006333:Heart Failure / Q000188:drug therapy*; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007263:Infusions, Parenteral; D008875:Middle Aged; D008991:Monitoring, Physiologic; D011217:Practolol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D011294:Prenalterol; D011669:Pulmonary Wedge Pressure / Q000187:drug effects; D013318:Stroke Volume / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
D000318:Adrenergic beta-Agonists; D011294:Prenalterol; D011217:Practolol