Low-dose captopril therapy in mild and moderate hypertension. Randomized comparison of twice daily vs three times daily doses.

We have investigated the antihypertensive activity of relatively low daily doses of captopril in patients with mild and moderate arterial hypertension. In a first trial, at the end of a 2-week placebo washout period, 18 patients with essential hypertension WHO Stage I or II were treated with captopril, 25 mg three times daily (t.i.d.), 25 mg twice daily (b.i.d.), 50 mg t.i.d., and 50 mg b.i.d., according to a randomized within-patient open design, with each regimen lasting for a 2-week period. In a second trial, 12 hypertensive patients not adequately controlled by chlorthalidone 25 mg daily as monotherapy (supine diastolic blood pressure at rest greater than 95 mm Hg), continued the diuretic treatment in combination with captopril, 25 mg t.i.d. and 25 mg b.i.d. according to a randomized within-patient open design. Analysis of variance did not reveal differences between the four captopril dosing schedules (1st trial), or between the two captopril dosing schedules (2nd trial). Both the patients on captopril monotherapy (1st trial) and those cotreated with chlorthalidone (2nd trial) showed lower systolic and diastolic blood pressure values on each captopril regimen compared to prerandomization values (all p less than 0.01). No relevant unwanted effects were noted. We conclude that in patients with mild or moderate essential hypertension, either untreated or resistant to chlorthalidone, captopril is effective in reducing blood pressure even at daily doses not exceeding 150 mg, without differences between a t.i.d. and a b.i.d. dosing schedule.