Clinical experience with captopril in the treatment of severe drug-resistant hypertension.

Thirty-three patients aged 12 to 77 years with severe hypertension uncontrolled on maximal combination therapy (mean arterial pressure on treatment 149 +/- 4 mm Hg) were treated with captopril, 45 to 450 mg daily for up to 30 months. Renovascular lesions were present in 11 and other renal disease in a further 15, of whom 8 had undergone renal transplantation. Good control (mean blood pressure less than 110 mm Hg) was achieved in 11 patients and moderate control (mean blood pressure 110 to 130 mm Hg) in 13. Captopril was given with a diuretic agent in 13 patients, with a diuretic agent and a beta-adrenoreceptor blocker in 13, and with three or more other agents in 7, of whom 4 had undergone renal transplantation. Side effects of rash, fever and gastrointestinal symptoms were observed, but there were no adverse effects on renal function or leukocyte counts. Severe hyperkalemia (potassium level greater than 6.0 mmol/liter) occurred in four patients despite the use of furosemide and low potassium diet. There was no significant correlation between the long-term hypotensive response and the initial decrease in blood pressure during captopril therapy.