Blood Pressure Pills More Effective When Taken at Night


October 7, 2010

October 7, 2010 - Taking medication at night instead of in the morning significantly increases efficacy in keeping blood pressure within a healthy range, according to a new study in Chronobiology International. Additionally, taking medication at night offers extra protection against heart attacks, strokes and other types of cardiovascular diseases.

Two articles in Chronobiology International, the international journal on how biological rhythms affect the systems of living things, cover the results of the MAPEC study.

Over the five-year study, the group of patients who took at least one of their medications at night experienced just one-third of the number of cardiovascular disease (CVD) episodes experienced by the group of patients who took all their medications in the morning.

"This study proves that the time of day when patients take their high blood pressure medications can make a huge difference due to the effect of the body's circadian rhythms on the actions of medications and because of the importance of preserving the normal day-night pattern of blood pressure in hypertension," said professor Ramón C. Hermida, Ph.D., director of bioengineering and chronobiology labs at the University of Vigo in Spain and lead investigator of the MAPEC Study. "Conventional treatment typically advises taking blood pressure medications in the morning. The MAPEC study shows that conventional treatment is not the most effective way to help patients with high blood pressure.”

Based on around-the-clock ambulatory blood pressure monitoring, the study found that taking at least one blood pressure medication at bedtime was best at normalizing sleep-time blood pressure. This is known to be the most sensitive predictor of a patient's five-year risk of CVD mortality. In addition, the study shows that taking medication at night is the best way to control daytime BP levels.

"Historically, medical professionals have operated on the assumption that sleep-time blood pressure levels will drop by 10 to 20 percent from daytime levels. However, for many patients – called nondippers – this doesn't happen and sleep-time therefore becomes a high risk period," said Francesco Portaluppi, M.D., of the Hypertension Center at the University Hospital of Ferrara in Italy and lead author of the perspectives article on the MAPEC study. "This study was the first to conclusively find that the time of day when medications are ingested not only affects efficacy but also CVD risk and these findings must fundamentally change the way patients are treated worldwide."

"Our body clocks are extremely powerful biological tools and this study offers insight and hard facts on how we can harness that power to help millions of people stay healthier and safer by ensuring that their blood pressure medications are taken as effectively as possible," said Michael Smolensky, editor of Chronobiology International.

More than 70 million people in the United States have hypertension.

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