Clinical relevance of long-term therapy with levodopa and orally active dopamine analogues in patients with chronic congestive heart failure.

Beneficial effects of long-term treatment with dopamine analogues in patients with congestive heart failure may result from their vasodilating properties, in particular from renal artery vasodilation. Oral application of levodopa results in increased dopamine plasma levels and can improve cardiac performance and renal function in patients with congestive heart failure. A daily levodopa dosage of at least 4 g appears to a prerequisite for long-term response to the drug. Because of frequent side effects including nausea, vomiting, and dyskinesia at this dosage, the clinical usefulness of levodopa seems to be limited to a minority of patients. Ventricular arrhythmias have been shown to increase significantly during long-term levodopa therapy, probably due to stimulation of myocardial beta receptors. Increased ventricular arrhythmias or significant central nervous side effects have not been observed after administration of ibopamine and fenoldopam, which are orally active analogues of dopamine. Both agents exhibit potent arterial vasodilating properties and have been shown to increase cardiac performance in patients with congestive heart failure after short-term administration. The long-term beneficial effects of ibopamine and fenoldopam in the treatment of congestive heart failure have not yet been clarified. However, available results are encouraging and warrant further clinical evaluation of these agents, as well as the development of new analogues of dopamine, in particular of potent vascular dopamine agonists.