Effects of antihypertensive drugs on the circadian blood pressure profile.

We compared the effect of beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, and calcium antagonists on the circadian blood pressure (BP) profile in essential hypertension. We reviewed all studies published between 1980 and August 1993 reporting the circadian efficacy of antihypertensive drugs and using ambulatory BP monitoring. In all, 815 patients with essential hypertension were assessed in 51 studies of eight different beta-blockers, six ACE inhibitors, and eight calcium antagonists. As main outcome measures, relative (percentage) BP reductions during the day and at night were compared between the three classes of antihypertensive drugs. Results were also separated for different dosing schemes (once and more than once daily). With all three classes of antihypertensive agents, the percentage night BP reduction was approximately 1-3% less as compared with percentage reductions during the day. Only for systolic BP (SBP) of the calcium antagonists administered once daily was this difference significant [2.2%, confidence interval (CI) 0.3-4.0%, p < 0.05], due to a higher statistical power in this group of agents. Our results show that beta-blockers, ACE inhibitors, and calcium antagonists are comparably effective during the day and at night, and no evidence indicates that either of the three agents is preferable to obtain the best possible antihypertensive effect at night.