THE ACUTE HEMODYNAMIC AND RENAL EFFECTS OF ORAL FELODIPINE AND RAMIPRIL IN HEALTHY-SUBJECTS

The aim of the present investigation was to compare the acute haemodyn amic and renal effects of the calcium antagonist felodipine with the A CE inhibitor ramipril and with placebo. Single oral doses of felodipin e 5 and 20 mg, ramipril 2.5 and 10 mg, and placebo were given to ten h ealthy subjects in a double-blind cross-over study. Blood pressure, he art rate, forearm blood flow (FBF), forearm vascular resistance (FVR), renal blood flow (RBF), renal vascular resistance (RVR), glomerular f iltration rate (GFR), filtration fraction (FF), diuresis, and sodium e xcretion were recorded for 4.75 h after administration. Felodipine 20 mg caused a significant fall in diastolic blood pressure, maximal 12% compared with placebo, while there were no significant effects of felo dipine 5 mg or the two doses of ramipril. Heart rate increased signifi cantly after both doses of felodipine, maximal 28% after the 20 mg dos e. There was also a small but significant increase in heart rate of 12 % after ramipril 2.5 mg. FVR fell significantly after both doses of fe lodipine, maximal 38% after the 20 mg dose. There were no significant changes in FVR after any of the ramipril doses. Both doses of felodipi ne and both doses of ramipril caused significant reductions in RVR. Ma ximal reduction, 33%, was found after felodipine 20 mg. There were no significant changes in GFR or FF with either drug. Felodipine caused a significant increase in natriuresis, maximal 129% while ramipril did not.