EFFECTS OF BENAZEPRIL AND HYDROCHLOROTHIAZIDE, GIVEN ALONE AND IN LOW-DOSE AND HIGH-DOSE COMBINATIONS, ON BLOOD-PRESSURE IN PATIENTS WITH HYPERTENSION

Objective: To assess the efficacy and safety of several combinations o f benazepril, an angiotensin-converting enzyme inhibitor, and hydrochl orothiazide, as compared with placebo, in the treatment of patients wi th essential hypertension. Design: A 6-week, randomized, double-blind, parallel study conducted at 24 centers. A placebo run-in period of 1 to 4 weeks preceded the double-blind phase.Participants and Setting: M ale and female outpatients, aged 18 years and older, were eligible to participate if their sitting diastolic blood pressure was between 95 a nd 114 mm Hg at the last two consecutive visits during the placebo pha se. Among the 334 patients who entered the double-blind phase, 17% wer e aged 65 years or older and 26% were black. Eleven patients withdrew because of adverse experiences, including two patients receiving place bo. Interventions: Patients received placebo; benazepril, 20 mg; hydro chlorothiazide, 25 mg; or combination therapy with benazepril/hydrochl orothiazide, 5/6.25 mg, 10/12.5 mg, 20/25 mg, 20/6.25 mg, or 5/25 mg, once daily for 6 weeks. Main Outcome Measures: The mean change from ba seline in sitting diastolic blood pressure at end point (last postrand omization measurement carried forward) in the double-blind phase. Comb ination therapy with benazepril/hydrochlorothiazide, 20/25 mg, was com pared with benazepril, 20 mg alone, and hydrochlorothiazide, 25 mg alo ne. Sitting systolic blood pressure and the effect of race and age on treatment efficacy were also evaluated. Results: Compared with placebo , all benazepril/hydrochlorothiazide combinations produced statistical ly significant reductions from baseline in sitting diastolic and systo lic blood pressures at study end point. In the benazepril/hydrochlorot hiazide, 20/25 mg, group, the adjusted mean changes in sitting diastol ic blood pressure at end point were statistically significantly greate r than those in the monotherapy treatment groups (benazepril, 20 me, P less than or equal to .05; hydrochlorothiazide, 25 mg, P less than or equal to .001) alone. All therapies were generally well tolerated. De creases in mean serum potassium level with hydrochlorothiazide monothe rapy were reduced or eliminated with combination therapy. Conclusion: Benazepril in combination with hydrochlorothiazide, including a low-do se combination of 5/6.25 mg, is effective in reducing sitting diastoli c and systolic blood pressure in patients with hypertension.