Quinapril, hydrochlorothiazide, and combination in patients with moderate to severe hypertension.

This 8-week, double-blind, multicentre study compared the efficacy and safety of the combination of quinapril and hydrochlorothiazide (HCTZ) with each drug as monotherapy. Outpatients with moderate to severe hypertension defined as supine diastolic blood pressure (DBP) > or = 105 mmHg and < or = 120 mmHg at the end of a 2 to 4-week placebo-baseline period were randomly assigned to one of the three treatments: once-daily 10 mg quinapril plus 12.5 mg HCTZ or monotherapy with these doses. After 4 weeks, the doses were to be doubled for the remaining 4 weeks. Three hundred and sixty-eight patients were randomized to double-blind medication; 346 completed the study. Seven patients withdrew due to lack of efficacy. Four patients withdrew due to side effects. In all three treatment groups, clinically significant reductions in DBP were achieved. Combination therapy was statistically more effective than each component taken as monotherapy. Adverse events were infrequent in all treatment groups. No patients experienced symptomatic hypotension or orthostatic hypotension.