A comparative study of the effects of nitrendipine and enalapril in essential hypertension

In this study, we compared the effects of nitrendipine (20-40 mg daily) and enalapril (20-40 mg daily) in 44 patients with mild to moderate essential hypertension. After a 4-week placebo period, the patients entered a double-blind, crossover study of 16 weeks, divided by a second 4-week placebo period. Sitting and standing blood pressures (standard mercurymeter) were measured every 2 weeks. Ten patients dropped out, so 34 patients were evaluable. Two patients dropped out because of surgery, one patient was withdrawn because of accelerating hypertension, and seven patients discontinued because of side effects (two on placebo, four on enalapril, and one on nitrendipine). Sitting blood pressures decreased from 172 +/- 3/107 +/- 1 to 159 +/- 3/94 +/- 1 mm Hg on nitrendipine (p less than 0.001) and to 157 +/- 4/96 +/- 2 mm Hg on enalapril (p less than 0.001). The heart rate did not change. Both compounds had no significant effect on serum lipids and on renal function. With regard to side effects, flushing occurred in 10 patients on nitrendipine and in 3 on enalapril (p less than 0.05); cough was noted in 3 patients on enalapril. When using a diastolic pressure less than 95 mm Hg as a response, 72% responded on nitrendipine and 64% on enalapril (n.s.). In conclusion, nitrendipine and enalapril, given as monotherapy, were equally effective antihypertensive agents in this group of patients with uncomplicated, moderate, essential hypertension. The use of either of the tested agents seems to be more limited by its specific side effects than the lack of antihypertensive efficacy.