The effect of oral fenoldopam (SKF 82526-J), a peripheral dopamine receptor agonist, on blood pressure and renal function in normal man.

The effect of a single oral dose of 100 mg of fenoldopam on renal function and blood pressure was investigated in seven healthy male subjects in a double-blind placebo controlled study. Mean diastolic blood pressure fell by 10 mm Hg, 45 min after oral dosing and then gradually returned to baseline values. There was an increase in pulse rate and a delayed rise in systolic blood pressure. Measured from 30 to 120 min after drug ingestion, mean effective renal plasma flow increased to 158% of the value observed after placebo; mean glomerular filtration rate rose to 109% of the placebo value. Measured from 120 to 210 min after administration of the drug, effective renal plasma flow and glomerular filtration rate had returned to baseline values. Fenoldopam produced a small increase in the mean sodium excretion rate which was not significantly different from the fall after placebo. No change was detected in urine flow or potassium excretion rate. Mean plasma renin activity increased three-fold 1 h after oral dosing. Plasma aldosterone did not show a parallel increase although the plasma concentration at 1 h was significantly higher than after placebo. The results show a pronounced renal vasodilator effect lasting about 2 h. The findings are consistent with marked DA1 receptor agonist activity.