Efficacy of once daily nitrendipine in essential hypertension--a study using ambulatory blood pressure monitoring.

To determine if the calcium channel blocking agent, nitrendipine, is effective as monotherapy we have performed a double-blind placebo-controlled crossover trial using 20 mg once daily or twice daily in 19 mild to moderate hypertensive patients. Blood pressure was measured by a random zero (RZ) sphygmomanometer and at home using the Remler semiautomatic BP recorder. The BP (RZ) was significantly reduced by twice daily nitrendipine compared to placebo (from 163/99 +/- 20/6 mmHg to 140/90 +/- 15/9 mmHg). Once daily drug administration reduced systolic BP only (163 +/- 20 to 144 +/- 17 mmHg). Remler BP confirmed that the maximum systolic and diastolic BP lowering effect was in the twice daily group while once daily drug did produce a significant lowering of BP but less than the twice daily dosage. This study suggests that twice daily nitrendipine caused a greater decrease in BP and was more consistent than once a day. The emergence of a new generation of automatic BP recorders should improve the evaluation of once daily therapeutic agents.