NEW DOPAMINE AGONISTS IN CARDIOVASCULAR THERAPY

Dopamine, a naturally occurring catecholamine, has been extensively used in intensive care for many years. Dopamine stimulates different types of adrenergic receptors: alpha-1 and -2, beta-1 and -2, and dopamine-1 and -2. The renal effects of dopamine are the result of dopamine-1 receptor (DA1) stimulation: renal vasodilation and natriuresis. DA2-receptor stimulation lowers plasma aldosterone and norepinephrine levels. Recently, several new dopamine agonists have been developed. Fenoldopam, a selective DA1-agonist, induces renal and systemic vasodilation with an increase in renal blood flow. This is accompanied by an increase in natriuresis and diuresis. Dopexamine, a DA1- and beta-2 agonist, is administered intravenously. It is used, like dopamine, in the treatment of congestive heart failure. However, the use of dopamine (and dopexamine) is limited by its unique intravenous availability. Ibopamine is an aselective dopamine agonist for oral use. Several clinical studies have demonstrated the efficacy of ibopamine in the treatment of patients with congestive heart failure and its mild renal effects.