Controlled Multicenter Study with Quinapril, Hydrochlorothiazide, and Combination in Patients with Moderate to Severe Hypertension

In an 8-week, double-blind, randomized, active-controlled, multicenter study with three parallel treatment groups, we compared the efficacy and safety of once-daily 20 mg quinapril plus 12.5 mg hydrochlorothiazide (HCTZ) with each drug as monotherapy in patients with moderate to severe hypertension. Hypertensive out-patients with supine diastolic blood pressure (DBP) > or = 105 and < or = 120 mm Hg at the end of a 2- to 4-week placebo-baseline period were randomly assigned to one of the treatment groups. Of the 323 patients who were randomized to double-blind medication, 297 completed the study, but 6 patients were excluded for violations of protocol; therefore, statistical analysis was performed in 291 patients. Only 7 patients withdrew owing to lack of efficacy (2 receiving combination therapy). In all three treatment groups, clinically significant reductions in DBP were achieved. Combination therapy was statistically more effective than each component in both evaluable data and intent-to-treat analyses. The incidence of adverse events (AE) was 24% in the quinapril monotherapy group, 14% in the combination therapy group, and 11% in the HCTZ monotherapy group. Orthostatic hypotension with related symptoms was observed in 4 patients (2 receiving quinapril monotherapy, 1 receiving HCTZ monotherapy, and 1 receiving combination therapy). Once-daily quinapril plus HCTZ provided increased reduction of DBP as compared with the monotherapies and was well tolerated in patients with moderate to severe hypertension.