Selective dopamine-1 agonist therapy in severe hypertension: Effects of intravenous fenoldopam

Abstract

To determine the effects of dopamine-1 agonist therapy in severe hypertension, blood pressure, heart rate, catecholamines and left ventricular function were studied in 18 patients (10 with renal disease) with diastolic blood pressure > 120 mm Hg (range 124 to 160) after intravenous fenoldopam therapy. Constant infusions of fenoldopam were titrated upward every 10 to 20 min from an initial dose of 0.1 μg/kg per min to a maximal dose of 0.9 μg/kg per min. The therapeutic goal or a supine diastolic blood pressure or <110 mm Hg was achieved in every patient within I h at an average dose of 0.34 ± 0.22 μg/kg per min. Blood pressure decreased from 214/134 ± 33/10 mm Hg at baseline to 170/96 ± 29/7 mm Hg (p < 0.0001) at 3 h, whereas heart rate increased from 77 ± 23 to 88 ± 21 beats/min (p < 0.01).Plasma norepinephrine increased during the fenoldopam infusion; epinephrine and dopamine levels did not change. Two indexes of left ventricular function (end-systolic dimension and isovolumic relaxation time) improved during the fenoldopam infusion, but mitral flow velocities during ventricular filling were unchanged. Side effects of intravenous fenoldopam were mild, transient and associated with the marked vasodilatory properties of the drug.Thus, fenoldopam is safe and effective as a parenteral monotherapy in patients with severe essential and renovascular hypertension. Preliminary data suggest that blood pressure reduction with selective dopamine-1 agonist therapy is accompanied by improved left ventricular function.