Nitrendipine vs. long-acting nifedipine in mild, moderate and severe hypertension

Long-acting nifedipine and nitrendipine, a nifedipine analogue, have been proposed for single-drug therapy of hypertension. In this study we compared the two preparations in three groups (10 subjects in each group) of mild (group 1), moderate (group 2), and severe (group 3) hypertensives. Drugs were administered for seven days (20 mg every 8 hr), according to a randomized, double-blind, crossover design. Blood pressure and heart rate readings were taken hourly, from 8 A.M. to 7 P.M., for the duration of the trial. In group 1, pressure was lowered to normal levels by both compounds and did not recover in the interval between one dose and the other, so that it remained normal throughout the day. In group 2, from an average of 170/109, values were reduced by the two preparations to 140/90 mm Hg within two hours, and then they tended to recover. This tendency was interrupted by the next dose. Because of this pattern, compared with the placebo period, pressure was substantially reduced during the twelve hours of the day; however, for a certain span it remained higher than normal. In group 3, the immediate responses to the two drugs were similar (from an average of 208/130, pressure was lowered to an average of 170/95 mm Hg), and then it tended to rise again and recovery was faster with nifedipine. Although pressure was significantly reduced throughout the day by both preparations, normotension was never achieved in this group. Neither drug induced a tachycardia reaction, altered renal or cardiac function, or affected body weight or plasma renin activity. The tendency to produce dependent edema was less pronounced with nitrendipine. In conclusion, these calcium channel antagonists were equally effective in mild and moderate hypertension, while in the severe from the action of nitrendipine was more persistent. Within the limits of the drug regimens used in this study, it seems that both preparations as monotherapy may be satisfactory in mild, questionable in moderate, and inadequate for severe hypertension, although the action of nitrendipine is more lasting.