Efficacy and safety of enalapril versus extended-release nifedipine for the treatment of mild-to-moderate essential hypertension: A multicenter 22- week study

The antihypertensive effects and tolerability of single daily doses of enalapril and extended-release nifedipine (nifedipine-ER) were compared in an open-label, randomized, parallel-group, 22-week treatment study involving 230 men and women (mean age, 55 years). Following a 3-week washout period, mean ±SD blood pressure levels were 153±17/99±4 mmHg in the enalapril group (n = 117) and 157±17/100±5 mmHg in the nifedipine-ER group (n = 113). Beginning at 5 mg once daily for enalapril and 30 mg once daily for nifedipine-ER, the dosage was titrated every 4 weeks for 16 weeks, up to a maximum of 40 mg for enalapril and 120 mg for nifedipine-ER. The treatment goal (satisfactory response) was to lower trough sitting diastolic blood pressure to <90 mmHg or by at least 10 mmHg to a level of <100 mmHg. At a mean daily dose of 16 mg of enalapril and 57 mg of nifedipine-ER, more than three quarters of each treatment group achieved a satisfactory response. The mean reductions in trough sitting blood pressure levels at the end of 22 weeks of treatment were 15/11 mmHg for enalapril and 21/13 mmHg for nifedipine-ER. The difference between treatments was significant only for the change in systolic blood pressure (P<0.05). However, enalapril was better tolerated than nifedipine-ER. The numbers of patients with adverse experiences and withdrawals from the study because of an adverse experience were significantly lower for enalapril than for nifedipine-ER (P<0.05). The incidence of abnormal laboratory findings was small and considered of no clinical importance in either group. These data suggest that enalapril and nifedipine-ER had approximately equal efficacy as once-daily antihypertensive treatments, but enalapril was better tolerated.