1. We randomized 475 men whose diastolic blood pressure was 92–109 mmHg to either placebo- or captopril-treated (37.5, 75 and 150 mg/day) groups for 7 weeks.
2. After 7 weeks, the placebo-treated patients were given hydrochlorothiazide (25 mg twice daily), as were two-thirds of each captopril-treated group, and they were observed for 7 additional weeks.
3. Captopril reduced blood pressure by 12.2 ± 0.8/9.4 ± 0.4 mmHg at 7 weeks (n = 323) and captopril plus placebo by 10.3 ± 1.9/10.2 ± 0.9 at 14 weeks (n = 83); placebo by 20 ± 1.7/3.4 ± 0.8 (n = 76); captopril plus hydrochlorothiazide by 24.4 ± 1.1/16.2 ± 0.6 (n = 173). The effect of low-dose captopril was similar to that of a high dose. The effect of twice-daily captopril appeared to be equal to that of thrice-daily treatment but monitoring studies are needed to confirm this.
4. Only 15 out of 384 (3.9%) of patients were dropped from the study because of adverse effects.
5. Low-dose captopril may be useful in patients with mild to moderate hypertension.
