Nitrendipine: evaluation of the duration of the antihypertensive effect at different doses using the conventional method and ambulatory monitoring of arterial pressure

To evaluate the effect-duration of nitrendipine in 20 moderate essential hypertensives (aged from 42 to 66, mean +/- SD: 55 +/- 7) when treated with 20 mg once or twice a day, we utilized the blood pressure standard method of measurement and the ambulatory monitoring. Blood pressure determinations were made during the follow-up at 2- week intervals for 3 months, each measurement being made with a mercury sphygmomanometer, 24 +/- 3 hours after the last dose; laboratory parameters, 2 24-hour blood pressure monitoring (ICR 5200, Spacelabs) and standard ECG were performed at baseline and after 3 months. Following a 2-week run-in period with placebo bid (at 10.00 am and 10.00 pm) a 20 mg morning dose of nitrendipine was started continuing the administration of the placebo tablet at 10.00 pm. The dosage was changed to a twice active daily regimen, with an increase in the daily dose (20 mg twice a day) in those patients whose diastolic blood pressure remained greater than 90 mmHg after a 4-week control. After the twelfth week, another 2-week placebo run-in followed the active treatment. Supine blood pressure recorded after 3-month therapy, showed a significant (p less than 0.0001) reduction in both systolic and diastolic mean values (22/15 mmHg) at the end of active treatment in the 16 patients who ended the trial. In particular, the responders to 20 mg (5 patients) showed a blood pressure reduction of 18 mmHg in comparison with the run-in period; in the other group of responders to increasing dosage of 40 mg (11 patients), we observed a 8 mmHg diastolic blood pressure reduction at 28 days and a successive 7 mmHg at the end of the treatment.(ABSTRACT TRUNCATED AT 250 WORDS)