Antihypertensives Before Bed May Lower BP

( — Taking antihypertensive medication at night may do a better job of controlling blood pressure than taking them in the morning, researchers found.

In a review and meta-analysis, evening administration significantly lowered 24-hour mean systolic and diastolic blood pressures compared with morning dosing, Ping Zhao, MD, of Sichuan University in China, and colleagues reported online in Cochrane Reviews.

“The clinical relevance of this decrease is not known, since very limited data have been reported for morning systolic and diastolic blood pressure, and mortality and morbidity data have not been reported,” they cautioned.

Research has shown that blood pressure has a distinct 24-hour circadian rhythm, typically involving a morning surge after arising from bed. Some studies have even shown a parallel between that morning surge and the incidence of cardiovascular events, Zhao and colleagues wrote.

So researchers have questioned whether the timing of delivery of antihypertensives can reduce excessive peaks in pressure that may pose additional risks.

To evaluate the relationship between time of administration and outcomes on all-cause death, cardiovascular morbidity, and reductions in blood pressure, the researchers conducted a review of the literature.

They examined 21 randomized controlled trials totaling 1,993 patients with primary hypertension who were treated with any of the six main classes of antihypertensives: ACE inhibitors, angiotensin receptor blockers (ARBs), calcium channel blockers (CCBs), diuretics, alpha-blockers, and beta-blockers.

Zhao and colleagues found that taking antihypertensives in the evening was associated with a significant reduction in mean 24-hour systolic blood pressure compared with morning administration (-1.71 mm Hg, 95% CI -2.78 to -0.65).

In subgroup analyses, there were no differences between beta-blockers, ACE inhibitors, ARBs, or CCBs for evening versus morning administration. However, there was a statistically significant effect for alpha-blockers and diuretics, but the finding was limited to results from only a few trials, the researchers cautioned.

They also observed a significant reduction in mean 24-hour diastolic blood pressure with evening administration compared with morning administration (-1.38 mm Hg, 95% CI -2.13 to -0.62), but they noted that there was significant heterogeneity among studies.


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