Combination of ramipril and hydrochlorothiazide in the treatment of mild to moderate hypertension: Part 1--A double-blind, comparative, multicenter study in nonresponders to ramipril monotherapy.

In a parallel-group multicenter study, the efficacy and safety of combination therapy with ramipril 5 mg plus hydrochlorothiazide 25 mg were compared double-blind with those of 5 mg and 10 mg ramipril monotherapy in patients with mild to moderate hypertension who had not responded adequately to ramipril 5 mg alone. Patients were initially treated single-blind for 1 week with ramipril 2.5 mg and 3 weeks with ramipril 5 mg. Of 240 patients enrolled, 165 were subsequently classed as nonresponders (diastolic blood pressure > 90 mmHg) and were randomized to one of the three double-blind treatments for a further 4 weeks. In the double-blind phase, the mean reductions in supine systolic and diastolic blood pressures at end point were significantly greater in the 5 mg plus 25 mg combination group (11.6/10.6 mmHg) than in the groups receiving ramipril 5 mg (6.2/5.9 mmHg; both p < 0.01) and ramipril 10 mg (7.4/7.1 mmHg; both p < 0.05). The proportion of responders at end point was also higher for combination therapy (72%) than for monotherapy (48% for ramipril 5 mg and 62% for ramipril 10 mg). All three treatments were well tolerated. Analysis of laboratory values revealed no clinically important changes.