Effects of nitrendipine and hydralazine on plasma catecholamines in essential hypertension.

We compared the efficacy and safety of nitrendipine with that of hydralazine in 21 subjects with essential hypertension. Nitrendipine or hydralazine was given in a double-blind manner after a placebo period. Dose was titrated to diastolic blood pressure (BP) less than or equal to 90 mm Hg and the dose established during titration was continued for 5 to 7 wk. Both supine and erect BP were decreased by both drugs, but heart rate was affected only minimally. Myocardial oxygen demand decreased only with nitrendipine (P less than 0.05), although the change may have been the result of somewhat higher systolic BP while on placebo. Hydralazine induced minimal changes in levels of plasma catecholamines, but plasma norepinephrine levels rose in subjects on nitrendipine. Side effects encountered with both drugs were much the same, although nitrendipine was more often associated with mild fatigue. There were mild elevations in liver function parameters in two subjects on nitrendipine. There was little difference between the effects of nitrendipine and hydralazine in hypertension.