denopamine and vesnarinone

The crucial issues in the management of congestive heart failure (CHF) are improvement of depressed myocardial contractility and reduction of excessive load. For this purpose, positive inotropic agents and vasodilators have been developed as new oral drugs. The former include Denopamine which possesses beta 1 stimulating effect, Xamoterol which is a unique agent acting as a beta 1-partial agonist, and Ibopamine, Docarpamine and Phosphodiesterase Inhibitors which possess both inotropic and vasodilating effects and are called "Inodilators". The latter include Angiotensin Converting Enzyme Inhibitors. In addition, new vasodilators, such as, Vasopressin Antagonist have also been developed. However, careful long-term clinical trials are required with regard to the efficacy and adverse effects before these agents are widely used with safety in the management of CHF.

Topics: Administration, Oral; Cardiotonic Agents; Deoxyepinephrine; Ethanolamines; Heart Failure; Humans; Phosphodiesterase Inhibitors; Piperidines; Propanolamines; Pyrazines; Quinolines; Quinolones; Vasodilator Agents; Xamoterol

The possible chronotropic and arrhythmogenic effects of newly-developed oral inotropic agents were studied in 60 patients with idiopathic dilated cardiomyopathy (NYHA class II-IV). Changes in heart rates and the incidence of arrhythmias were evaluated using ambulatory electrocardiography. Denopamine 30 and 60 mg (beta 1 agonist), xamoterol 200 and 400 mg (beta 1 partial agonist) and OPC-8212 60, 90 and 120 mg (non-catecholamine) were sequentially administered for 10 +/- 2 months. Denopamine slightly increased heart rate throughout the day. Denopamine 60 mg caused excessive tachycardia in patients with atrial fibrillation, and could be used without digoxin. With xamoterol, maximum heart rate decreased during the daytime, while heart rate increased at night. Xamoterol was highly effective in patients with atrial fibrillation who not only had excessive tachycardia during exercise but marked bradycardia at night. Xamoterol increased the severity of heart failure in two patients who belonged to NYHA class IV, whose heart rates at rest had exceeded 100 beats/min. OPC-8212 did not affect heart rate, and was considered an ideal inotropic agent. None of these agents aggravated arrhythmias or caused sustained ventricular tachycardia. It was concluded that not only the severity of heart failure but the chronotropic and arrhythmogenic effects should be considered when choosing inotropic agents.

Topics: Administration, Oral; Adult; Aged; Aged, 80 and over; Arrhythmias, Cardiac; Atrial Fibrillation; Cardiomyopathy, Dilated; Cardiotonic Agents; Circadian Rhythm; Digitalis; Drug Evaluation; Electrocardiography, Ambulatory; Ethanolamines; Female; Heart Rate; Humans; Male; Middle Aged; Plants, Medicinal; Plants, Toxic; Propanolamines; Pyrazines; Quinolines; Xamoterol