Comparative Efficacy and Safety of Enalapril and Sustained-Release Nifedipine in Patients with Mild to Moderate Hypertension

Abstract

The long acting angiotensin-converting enzyme inhibitor enalapril was compared with the calcium channel blocker nifedipine as sustained-release formulation in 136 patients with mild to moderate hypertension. This multicentre study was carried out in a double-blind, double-dummy fashion by 28 cardiologists in private practice. After a 2-week placebo period, patients were randomly allocated to 2 treatment groups; the first group received enalapril 20 mg daily (n = 68), and the second group received sustained-release nifedipine 20 mg twice daily (n = 68). The duration of treatment was 12 weeks. In both groups, hydrochlorothiazide 25 mg was added at week 4 if diastolic blood pressure remained greater than 90 mm Hg. At week 8, if the target diastolic pressure of less than 90 mm Hg was not achieved, the dosage of hydrochlorothiazide was increased to 50mg. The clinical characteristics of the patients in each group were comparable. After 4 weeks of treatment, the reduction in supine diastolic blood pressure was similar in both groups (12.1 mm Hg in the enalapril group vs 10.3 mm Hg in the nifedipine group). Moreover, although the difference between the groups was more noticeable after 12 weeks of treatment (16.3 vs 13.9 mm Hg, respectively), it did not reach significance. The number of patients experiencing clinical adverse effects was significantly greater in the nifedipine group than in the enalapril group [33 (48.5%) vs 18 (26.5%), respectively]. The most common complaints of patients administered nifedipine included swollen ankles, flushing and headaches, whereas complaints in the enalapril group included cough, asthenia, and epigastralgia. Three patients were withdrawn from the study because of side effects in the enalapril group and 10 were withdrawn from the nifedipine group. These results indicate that enalapril and sustained-release nifedipine are equally effective in controlling mild to moderate hypertension. However, enalapril was much better tolerated in this study.