Double-blind comparison of the efficacy and safety of trandolapril 2 mg and hydrochlorothiazide 25 mg in patients with mild-to-moderate essential hypertension

This multicenter international trial recruited 205 patients from 16 investigators. After a 4-week, single-blind placebo run-in, patients were randomized to receive 16 weeks of trandolapril 2 mg/day (68 patients), hydrochlorothiazide (HCTZ) 25 mg/day (68 patients), or the combination (69 patients). Morning predosing supine diastolic blood pressure (DBP) was the primary efficacy measurement. Intention-to-treat analysis showed significant decreases in all three groups in mean (± SEM) supine DBP throughout the study, with no significant differences at week 16 between trandolapril (-10.6 ± 1.3 mm Hg) and HCTZ (-10.9 ± 1.3 mm Hg). The combination gave a significantly greater reduction than either drug alone (-15.1 ± 1.13 mm Hg). Blood pressure was normalized in the combination group in 67% of patients, a significantly higher proportion than either trandolapril (63%) or HCTZ (60%; p = 0.04). Each treatment was well tolerated. The incidence of adverse events was similar in all three groups. Trandolapril 2 mg once daily is an effective antihypertensive agent, comparable to HCTZ. Furthermore, the combination of the two drugs was shown to enhance the antihypertensive effect of the two compounds alone. © 1994 Raven Press, Ltd., New York.