Acute intravenous and sustained oral treatment with the beta1 agonist prenalterol in patients with chronic severe cardiac failure.

Abstract

SUMMARY Prenalterol, a beta, agonist, was given in a single blind acute intravenous study to seven patients with cardiac failure (New York Heart Association class II and III). It was then given in a double blind crossover study of sustined oral prenalterol to six of them. As a result of dose titration studies the oral dose of prenalterol given was 100 mg twice a day in all patients. Erect bicycle sprint tests were performed to exercise tolerance before and after treatment had been started. Cardiac function was assessed at rest and during graded supine bicycle exercise by determining haemodynamic indices using a Swan-Ganz catheter and radionuclide left ventricular ejection fractions. In the intravenous study cardiac function was assessed at rest and during exercise after a control infusion of dextrose and after an infusion of 5 mg prenalterol. In the oral crossover study a placebo or prenalterol were given for two periods of two weeks; at the end of each period exercise tolerance was measured and cardiac function assessed at rest and during exercise.Throughout Accepted for publication 13 December 1983 exercise78 in patients with cardiac failure. There have been only preliminary reports regarding the efficacy of oral prenalterol treatment in the management of patients with chronic cardiac failure.7 9 10We report a single blind acute study with intravenous prenalterol, followed by a double blind crossover study of oral prenalterol given for two weeks in patients with chronic severe cardiac failure. Symptoms, exercise tolerance, rest and exercise haemodynamic indices, and left ventricular ejection fraction were assessed at rest and during graded supine exercise. The effects on cardiac function of prenalterol given intravenously and orally were compared to determine whether the beneficial acute 530

Are the clinical benefits of oral prenalterol in ischaemic heart failure due to beta blockade? A six month randomised double blind comparison with placebo.

“…Additionally, the greater number of patients in our study may have enabled us to observe changes not apparent in the small groups of Lambertz (n= 16)34 and Currie (n= 6). 35 The dose of prenalterol used in the Lambertz study34 was lower than that which we used with resulting serum concentrations approximately half of those we obtained. In Currie's study35 the treatment period was short so that it would have missed the clinical benefits which became apparent in our study after three months' treatment.…”

The cardiovascular pharmacology of xamoterol, cicloprolol, prenalterol and pindolol in the anaesthetised dog.

“…Prenalterol, though of benefit in acute studies, was unsuccessful on chronic dosing (Currie et al, 1984;Lambertz et al, 1984), and pindolol has been shown to have deleterious effects on cardiac contraction in patients with ischaemic heart failure (Rousseau et al, 1984;Binkley et al, 1986).…”