Background: There is currently no clear evidence that dual neutral endopeptidase-angiotensin-converting enzyme inhibitors have effects on angiotensin-converting enzyme, renin, or blood pressure that are different from specific angiotensin-converting enzyme inhibitors in humans. Methods and results In a double-blind, placebo-controlled crossover study single oral doses of the dual neutral endopeptidase-angiotensin-converting enzyme inhibitor, 10 mg BMS-186716 and the angiotensin-converting enzyme inhibitor fosinopril (20 mg) were administered to 9 normotensive subjects with induced mild sodium depletion. Values for area under the time curve from 0 to 24 hours [AUC(0-24)] for the plasma angiotensin II/angiotensin I ratio and for angiotensin II were similar for 10 mg BMS-186716 and 20 mg fosinopril, Plasma atrial natriuretic peptide decreased significantly after 20 mg fosinopril (9 +/- 3 pg/mL; P < .05 versus 10 mg BMS-186716 and placebo) compared with 10 mg BMS-186716 (16 +/- 5 pg/mL) and placebo (16 +/- 5 pg/mL), BMS-186716, 10 mg, significantly increased urinary atrial natriuretic peptide from baseline by 2 +/- 1.3-fold (P < .05 versus placebo and 20 mg fosinopril). AUC(0-24) of plasma active renin did not differ significantly between 10 mg BMS-186716 (3898 +/- 333 pg.h.mL(-1)) and 20 mg fosinopril (4383 +/- 302 pg.h.mL(-1); difference not significant). Both drugs decreased blood pressure, but the AUC(0-24) of the changes in mean blood pressure differed significantly from placebo (79 +/- 84 mm Hg.h) only for 20 mg fosinopril (181 +/- 6 mm Hg.h; P < .05) but not for 10 mg BMS-186716 (118 +/- 7 mmHg.h), Conclusions: In this model, single oral doses of 10 mg BMS-186716 and 20 mg fosinopril induced similar 24-hour in vivo angiotensin-converting enzyme inhibition. BMS-186716, 10 mg, increased urinary atrial natriuretic peptide and blunted the expected decrease in plasma atrial natriuretic peptide caused by angiotensin-converting enzyme inhibition. BMS-186716, 10 mg, did not inhibit plasma active renin rise compared with 20 mg fosinopril, A single oral dose of 10 mg BMS-186716 had a shorter blood pressure-lowering effect than 20 mg fosinopril.