Racial Differences in Response to Low-dose Captopril Are Abolished by the Addition of Hydrochlorothiazide

1 In a randomised study, 475 men with diastolic blood pressures of 92-109 mm Hg received either placebo or captopril 37.5 mg, 75 mg or 150 mg/day for 7 weeks. 2 After 7 weeks patients taking placebo were given hydrochlorothiazide 25 mg twice daily, as were two-thirds of each group taking captopril and they were observed for 7 additional weeks. 3 Captopril reduced blood pressure by 12.2 +/- 0.8/9.4 +/- 0.4 mm Hg at 7 weeks (n = 323) and captopril plus placebo reduced it by 10.3 +/- 1.9/10.2 +/- 0.9 mm Hg at 14 weeks (n = 83); placebo by 2.0 +/- 1.7/3.4 +/- 0.8 mm Hg (n = 76); and captopril plus hydrochlorothiazide by 24.4 +/- 1.1/16.2 +/- 0.6 mm Hg (n = 173). The effect of low-dose captopril was similar to that of high doses. 4 White patients responded better than blacks, with a blood pressure reduction of 14.7 +/- 1.1/10.7 +/- 0.6 mm Hg (n = 170) v 9.1 +/- 1.2/8.0 +/- 0.7 mm Hg (n = 151). This difference was abolished by the addition of hydrochlorothiazide. 5 Only 15/384 (3.9%) of patients were dropped from the study because of adverse effects. 6 The prescription of low-dose captopril might be extendable to patients with mild to moderate hypertension.