Long-term efficacy of captopril in renovascular and essential hypertension.

Captopril was used in primary and long-term treatment of 40 treatment-resistant hypertensive patients. Of these, 21 had renovascular hypertension, seven unilateral and fourteen bilateral, and 19 had essential hypertension, 10 with high-renin and 9 with normal-renin profiles. All patients were off treatment when started on captopril therapy and were treated for at least 12 months, on the average for more than 2 years. The strategy of systematic drug withdrawal used to find the lowest effective dose of captopril led to average doses of 150 to 300 mg/day. A diuretic agent was added in 17 of the 40 patients when diastolic pressure remained greater than 105 mm Hg and a beta-adrenergic blocking agent was added for tachycardia or additional pressure control in 16 patients. Captopril alone was effective in 14 of the 40 patients. In all groups, mean supine and standing blood pressure levels were maintained at less than 140/90 mm Hg without evidence of decreased effectiveness over time. Control and treatment systolic pressures were higher in patients older than 50 years. For patients of all ages, systolic but not diastolic pressure during captopril treatment was higher in the supine position than standing. Plasma renin activity remained significantly elevated over time and aldosterone excretion usually decreased despite concurrent diuretic therapy. Captopril alone or in combination with a diuretic or beta-adrenergic blocking agent is effective in long-term treatment of drug-resistant renovascular and essential hypertension.