Monotherapy of essential hypertension with a converting-enzyme inhibitor.

The antihypertensive effectiveness of twice-daily dosing with the converting enzyme inhibitor, captopril, was examined in a multicenter study of 294 patients (181 white, 111 black, two oriental) with essential hypertension whose supine diastolic blood pressure (SDBP) was 95 mm Hg or higher after 4 to 6 weeks of preliminary placebo administration. In this double-blind study, the patients were randomized into one placebo and three captopril-treated groups: twice-daily placebo (n = 77) or twice-daily captopril 25 mg (n = 77), 50 mg (n = 71), or 100 mg (n = 69). The average decreases in SDBP after 8 weeks of treatment were 5.2%, 7.7%, 11.7%, and 10.5%, respectively. Only the two higher dose groups differed significantly from the placebo group; they also differed from the lowest dose group. The proportions of patients classified as having normalized pressures (SDBP less than 90 mm Hg) in the four groups were 39%, 47%, 70%, and 50%. If the results were analyzed by race, all three captopril-treated groups differed significantly from the placebo-treated group in the white patients but not in the black patients. However, direct comparisons between the white and black groups showed a difference only at the low, 25 mg twice daily (b.i.d.), captopril dose. Thus, although conventionally given on a three-times daily basis, the twice-daily (12-hourly) administration of captopril provides effective antihypertensive treatment in doses of 50 or 100 mg b.i.d. Moreover, white patients also exhibit a significant response to captopril at doses as low as 25 mg b.i.d.(ABSTRACT TRUNCATED AT 250 WORDS)