Effect of enalapril and nifedipine on orthostatic hypotension in older hypertensive patients

OBJECTIVE: To compare the effect of enalapril with long-acting nifedipine o n orthostatic hypotension in older patients. DESIGN: A prospective, double blinded, cross-over study. SETTING: The outpatient clinic of a university hospital. PARTICIPANTS: Thirty-nine patients aged 65 years or older with systolic blo od pressure (SBP) of 140-190 mm Hg and diastolic blood pressure (DBP) of 90 -110 mm Hg. INTERVENTION: Enalapril 5-20 mg od or nifedipine 30-90 mg od fur 8 weeks, f ollowed by 4 weeks washout and cross-over for a second 8-week period. MEASUREMENTS: Supine and standing 0-, 1-, and 5-minutes blood pressure was recorded before and at the end of each treatment period. RESULTS: At baseline, SEP was 158.8 +/- 8.7 mm Hg, and DBP was 97.1 +/- 5.9 mm Hg. There was a decline in SEP of 6.1 +/- 2.7 mm Hg and 8.4 +/- 4.1 mm Hg after 1 and 5 minutes of standing, respectively. Both agents caused a si gnificant decline in supine blood pressure. Enalapril: supine SEP 158.8 1 8 .7 to 143 +/- 7.3 mm Hg; supine DBP 97.1 +/- 5.9 to 85.1 +/- 5.1 mm Hg (P = .0001). The drop in SEP after standing for 5 minutes was only 2.4 +/- 1.6 m m Hg with no change in diastolic values. A greater than or equal to 10 mm H g drop in SEP was observed in only three patients, and no patient experienc ed a decline of 20 mm Hg or more. Nifedipine: supine SEP: 160.3 +/- 9 to 14 5.3 +/- 8.1 mm Hg; supine DBP: 96.3 +/- 5.7 to 86.3 +/- 5,8 (P =.0001). Nif edipine induced an orthostatic decline in SEP values; there was an 8.7 +/- 4.8 mm Hg difference between supine and 5 minutes standing values (P =.0005 ) without change in diastolic values. An orthostatic decline in SEP of grea ter than or equal to 10 mm Hg occurred in 13 patients, and there was a drop of greater than or equal to 20 mm Hg in six patients. The cross-over of en alapril and nifedipine reproduced the hypotensive effect and reversed the p ostural effect. (P =.0002 nifedipine vs enalapril) CONCLUSIONS: Enalapril and nifedipine were equipotent in reducing supine bl ood pressure levels. Enalapril also reduced the number of orthostatic episo des significantly, whereas nifedipine aggravated this phenomenon.