A double blind comparative study of lisinopril and enalapril in patients with essential hypertension

The efficacy and safety profiles of lisinopril (10-40 mg) and enalapril (5-20 mg) were compared in 169 hypertensive patients during 12 weeks' treatment in a randomised double-blind parallel group study. BP was measured hourly for the first 8 hours following the first dose of lisinopril 10 mg and enalapril 5 mg. The peak reduction in sitting systolic and diastolic BP occurred approximately 6 hours post dose in both groups. At 8 hours post dose lisinopril had reduced sitting systolic and diastolic BP by 2.9 mmHg and 3.5 mmHg (P = 0.02) respectively, more than enalapril with similar results for standing BP. One patient on enalapril developed first dose postural hypotension. After 12 weeks' therapy lisinopril produced a greater decrease (P less than 0.05) in BP than enalapril. Sitting BP decreased by 25/15 mmHg on lisinopril and 17/12 mmHg with enalapril. Standing BP decreased by 24/14 mmHg compared with 16/10 mmHg on enalapril. Eighteen patients did not complete the study, 8 on lisinopril (6 adverse events, 1 uncontrolled BP, 1 protocol violator) and 10 on enalapril (8 adverse events, 1 uncontrolled BP, 1 protocol violator). Overall, the results indicated that while both drugs are well tolerated, the dose range of lisinopril 10-40 mg may produce a greater antihypertensive effect than enalapril 5-20 mg.