A comparison of long acting nifedipine and enalapril in elderly hypertensives: a randomised, single-blind, cross-over study.

The effects of nifedipine and enalapril on blood pressure (BP), heart rate, plasma and urine electrolyte, plasma renin activity (PRA), aldosterone and catecholamines, were studied in ten elderly hypertensive subjects in a randomised, single-blind, cross-over trial. Both nifedipine and enalapril were effective in lowering supine and erect systolic and diastolic BP, with nifedipine causing a significant (P less than 0.05) rise in heart rate. Arterial pressure rose to pre-treatment levels on withdrawal of both drugs. Plasma glucose fell significantly (P less than 0.02) on enalapril therapy, whilst no other biochemical changes were observed. PRA, aldosterone and adrenaline rose on nifedipine therapy whereas PRA showed a greater rise on enalapril with a fall in plasma aldosterone and no change in plasma adrenaline. Plasma noradrenaline was not altered by either agent. Unacceptable side effects occurred in patients taking nifedipine resulting in discontinuation of therapy in 2 patients and death in another. Nifedipine or enalapril monotherapy is effective in lowering BP in the elderly hypertensives. Although more experience is needed, the side effect profile of both agents especially enalapril, appears satisfactory.