Comparison of the efficacy and safety of trandolapril and captopril for 16 weeks in mild-to-moderate essential hypertension. Investigator Study Group.

This multicenter international trial recruited 180 patients from 27 investigators. After a 4-week, single-blind placebo run-in, patients were randomized double-blind to 16 weeks of trandolapril 4 mg o.d. or captopril 50 mg b.i.d. If blood pressure was not normalized at 8 weeks, hydrochlorothiazide (HCTZ) 25 mg was added. Morning predosing supine diastolic blood pressure (DBP) was the primary efficacy measurement. At 8 weeks, the intention-to-treat analysis showed a significant difference for supine DBP (mean +/- SEM) between the two groups: trandolapril -13.5 +/- 0.9 mm Hg; captopril -10.1 +/- 1.0 mm Hg (p = 0.007). The proportion of patients whose blood pressure was normalized was 61% for trandolapril and 44% for captopril (p = 0.02). At 8 weeks, 26% of the trandolapril group received HCTZ compared with 38% taking captopril. The addition of HCTZ further increased the antihypertensive effect in patients who had shown only moderate reductions in blood pressure after drug monotherapy. Both treatments were well tolerated clinically and biochemically. Withdrawals owing to adverse events were three from trandolapril and eight from the captopril group. Trandolapril given once daily is an effective and well-tolerated antihypertensive agent that, in this study, exhibited better efficacy compared with captopril. When blood pressure is not sufficiently controlled with monotherapy, the combination of trandolapril and HCTZ enhances the antihypertensive effect.