Renovascular hypertension: treatment with the oral angiotensin-converting enzyme inhibitor enalapril.

Sixteen patients with an established diagnosis of renovascular hypertension were entered in an open study of enalapril (MK421), an oral angiotensin-converting enzyme (ACE) inhibitor, for treatment of their hypertension. Initial blood pressure was 178.9 +/- 6.3/106.2 +/- 3.1 mm Hg during conventional therapy on a median of 3 different antihypertensive agents. All antihypertensive therapy was ceased and the patients admitted to hospital. Following introduction of enalapril, blood pressure fell to 161.5 +/- 6.9/90.6 +/- 4.1 mm Hg at 24 h (p less than 0.01 systolic and diastolic). Blood pressure control (diastolic blood pressure, phase V, less than 95 mm Hg) was achieved with monotherapy in 7 patients and in a further 5 patients with addition of a diuretic. Renal function was compromised in 4 patients, requiring cessation of enalapril in 2 instances. Enalapril is an oral ACE inhibitor useful in the treatment of renovascular hypertension. Close monitoring of renal function is necessary during the introduction of enalapril therapy in patients with renovascular hypertension.