Effect of Enalapril and Nifedipine on Orthostatic Hypotension in Older Hypertensive Patients

OBJECTIVE: To compare the effect of enalapril with long-acting nifedipine on 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 blood 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 for 8 weeks, followed 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, SBP was 158.8 ± 8.7 mm Hg, and DBP was 97.1 ± 5.9 mm Hg. There was a decline in SBP 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 significant decline in supine blood pressure. Enalapril: supine SBP 158.8 ± 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 SBP after standing for 5 minutes was only 2.4 ± 1.6 mm Hg with no change in diastolic values. A ≥ 10 mm Hg drop in SBP was observed in only three patients, and no patient experienced a decline of 20 mm Hg or more. Nifedipine: supine SBP: 160.3 ± 9 to 145.3 ± 8.1 mm Hg; supine DBP: 96.3 ± 5.7 to 86.3 ± 5.8 (P = .0001). Nifedipine induced an orthostatic decline in SBP 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 SBP of ≥ 10 mm Hg occurred in 13 patients, and there was a drop of ≥ 20 mm Hg in six patients. The cross-over of enalapril and nifedipine reproduced the hypotensive effect and reversed the postural effect. (P = .0002 nifedipine vs enalapril) CONCLUSIONS: Enalapril and nifedipine were equipotent in reducing supine blood pressure levels. Enalapril also reduced the number of orthostatic episodes significantly, whereas nifedipine aggravated this phenomenon. J Am Geriatr Soc 48:807–810, 2000.