Captopril and kidney function in renovascular and essential hypertension.

In the present study 25 patients with various forms of severe hypertension (essential hypertension: n = 12; renovascular hypertension: n = 11; unilateral small kidney: n = 2), which were treated with captopril for a mean control period of 34.9 months, were investigated. Reduction of mean blood pressure under captopril was comparable in all subgroups. However, patients with renovascular hypertension showed a significant increase in serum creatinine from 117 to 162 mumol/l (p less than 0.05) after 34.9 months, whereas in essential hypertensives even a slight decrease could be observed (113 vs. 111 mumol/l). Serum creatinine of the 2 patients with unilateral small kidney remained within the normal range. Changes in creatinine were markedly higher in cases with bilateral renal artery stenosis and/or in those with a very high initial plasma renin activity (greater than 15 ng/ml X 3 h). Our findings underline the necessity of cautious application of captopril in patients with renovascular hypertension.