Underestimation of 24-hour hypotensive efficacy of nifedipine GITS versus enalapril: Ambulatory recording as an adjunct to clinical blood pressure measurement

Aims: Short-acting calcium entry blockers should be used primarily in slow- release form. Furthermore, studies of the antihypertensive efficacy of drug s can be negatively influenced by between 15% and 30% of the enrolled patie nts not being hypertensive according to ambulatory blood pressure (BP) meas urement. Thus, a randomized double-blind multicenter parallel-group study w as conducted to compare the effect of nifedipine GITS (gastrointestinal the rapeutic system) with enalapril. Methods and results: After a 2-week placeb o run-in period, 186 patients with a sitting diastolic BP greater than or e qual to 95 mmHg were enrolled for an 8-week treatment period. They received 30-60 mg nifedipine GITS or 5-10 mg enalapril. Diastolic BP fell comparabl y from 99 to 87 mmHg (p < 0.01) in the nifedipine GITS group, and from 100 to 88 mmHg (p < 0.01) in the enalapril group. The increase in BP 2 h before waking, however, was suppressed significantly more by nifedipine. Furtherm ore, this study highlighted the existence of "white-coat" hypertension in a number of patients, especially when clinical BP was used to identify hyper tension. Of the patients who had been identified as hypertensive before ran domization by standardized BP measurement, 53 (28.5%) were identified as no n-hypertensives by 24-h BP monitoring. This led to an underestimation of th e efficacy of the antihypertensive therapy. Conclusion: Nifedipine GITS as well as enalapril are comparably effective antihypertensive drugs.