Fixed-dose combination therapy with trandolapril and verapamil SR is effective in primary hypertension

We assessed the efficacy of monotherapy with trandolapril, an angiotensin converting enzyme (ACE) inhibitor, and of verapamil slow-release (SR), a calcium antagonist, each in a range of three doses as monotherapy, and in the nine possible combinations of therapy in patients with stage I to III diastolic hypertension. After 4 weeks of single-blind placebo, 746 patients in 39 study centers were randomized to one of the 16 double-blind treatments for 6 weeks (placebo; verapamil SR monotherapy 120, 180, or 240 mg; trandolapril monotherapy 0.5, 2, or 8 mg; and trandolapril/verapamil SR combinations 0.5/120, 0.5/180, 0.5/240, 2/120, 2/180, 2/240, 8/120, 8/180, or 8/240 mg. Both mono- and combination therapies achieved the primary efficacy parameters: lowered supine diastolic blood pressure (at trough) more than placebo, P < .01 (except 0.5 mg trandolapril, 0.5/180 and 2/120 combinations, P < .05, and the 120 mg verapamil SR, P = NS). The therapies yielded a trough to peak ratio of >0.52 and had higher percentages of responders as compared with placebo (P < .01, < .05). Supine systolic blood pressures were lowered more by combination therapy than the respective monotherapies, P < .05, P < .01, except the 8/120 combination. Combination therapy was more effective than monotherapy for sitting diastolic blood pressure, P < .05. The percentage of patients with adverse reactions were similar for mono- and combination therapy. Trandolapril had a greater "apparent" incremental effect on the systolic blood pressure reductions than verapamil SR.