The Antihypertensive Properties of the Angiotensin-Converting Enzyme Inhibitor Moexipril Given Alone or in Combination with a Low Dose of a Diuretic

The antihypertensive characteristics of the angiotensin-converting enzyme inhibitor moexipril were evaluated in 413 patients with baseline setting diastolic blood pressures between 95 and 114 mm Hg. The study was double blind, with patients randomized to placebo or to differing doses of moexipril alone or in combination with a low dose of hydrochlorothiazide. Compared with placebo, moexipril 3.75 mg daily was not different, but single daily doses of 7.5, 15, and 30 mg were significantly more effective (as measured at trough, approximately 24 h after dosing) in decreasing the diastolic blood pressuring during an 8-week treatment period. The dose-response relationship indicated that no additional blood-pressure-lowering effect occurred above 15 mg daily. Hydrochlorothiazide 12.5 mg was not significantly more effective than placebo, but the combinations of the diuretic with moexipril doses of 3.75, 7.5, and 15 mg all produced significant antihypertensive actions. Interestingly, the 3.75-mg moexipril--hydrochlorothiazide combination was equally as efficacious as the higher doses. The combinations were all more effective than their respective moexipril and hydrochlorothiazide monotherapies. There were no meaningful laboratory changes except for decreased potassium concentrations in the patients on diuretic alone; this effect was attenuated in the low-dose moexipril combination. Only 14 of the 413 patients who entered the double-blind study period (3%) discontinued treatment because of adverse experiences. Thus, moexipril is a well-tolerated drug that has clear antihypertensive efficacy as a single agent in once-daily doses of 7.5--30 mg. When combined with hydrochlorothiazide 12.5 mg, it is effective in daily doses as low as 3.75 mg.