Blood Pressure Drugs More Effective When Taken at Bedtime: Study
Wed, April 21, 2021

Blood Pressure Drugs More Effective When Taken at Bedtime: Study

Researchers found that there's a lower risk of cardiovascular problems when taking medicine at bedtime / Photo Credit: Pixabay


Taking medication for high blood pressure at night could increase its effectivity compared to when taken in the morning, a new study suggests.

Published in the European Heart Journal, the Hygia Chronotherapy Trial found that taking such medication at bedtime allows people with high blood pressure to have better-controlled blood pressure and lowers the risk of death and illness due to heart or blood complications.

The trial is the largest study to examine how the time of day when medication is taken affects the risk of cardiovascular problems. It is part of a larger study known as the Hygia Project. Results could change how doctors prescribe these drugs—although the question as to why such an effect takes place remains.


Lowered risks

The randomized trial involved 19,084 patients who took their pill either upon waking up or at bedtime. Researchers checked the patients' blood pressure for 48 hours once a year for over six years.

The patients also adhered to a routine of daytime activity and night-time sleep, meaning the results of the study may not apply to people who work night shifts. At the end of the trial, the researchers found that the patients who took their medication at bedtime were 45 percent less likely to die or suffer from cardiovascular problems compared to those who took their medication in the morning.

These results came after the researchers took into account other factors—age, sex, type 2 diabetes, kidney disease, smoking and cholesterol levels—that may affect the findings, Science Daily reports. Science Daily is an American website that publishes lightly edited press releases about science, studies, and discoveries.



Individual outcomes show lower risks of death due to heart or blood vessel problems (66 percent), heart attack (44 percent), coronary revascularisation or the widening of blocked or narrowed coronary arteries (40 percent), heart failure (42 percent), and stroke (49 percent).

While there is no preferred time indicated on current guidelines on treating hypertension, lead researcher Ramón C. Hermida said the most common prescription is to take the medication in the morning. He said this is based on the "misleading goal of reducing morning blood pressure levels."

"Furthermore, there are no studies showing that treating hypertension in the morning improves the reduction in the risk of cardiovascular disease," the lead researcher noted.


Significant markers

Monitoring the patients' blood pressure for 48 hours was what made the trial unusual since monitoring usually lasts for 24 hours, but the 48-hour monitoring period provided the researchers with accurate information on the patients' average blood pressure over the said duration. This includes how much blood pressure decreased while the participants were asleep.

Results of the blood pressure monitoring showed that patients who took their medication at bedtime had notably lower blood pressure both during the day and night, with their blood pressure dropping more while asleep, compared to those who took their medication in the morning.

The progressive decrease in night-time blood pressure in the follow-up period was the key indicator of a reduced risk of heart disease.



"The findings from the Hygia Chronotherapy Trial and those previously reported from the Hygia Project indicate that average blood pressure levels while asleep and night-time blood pressure dipping...are jointly the most significant blood pressure-derived markers of cardiovascular risk," Hermida said.

"Accordingly, round-the-clock ambulatory blood pressure monitoring should be the recommended way to diagnose true arterial hypertension and to assess the risk of cardiovascular disease."

He added that decreasing the average blood pressure at night is as protective as increasing the sleep-time relative decline in blood pressure to normalize lower patterns of blood pressure levels. This constitutes a "joint novel therapeutic target for reducing cardiovascular risk."



While taking medication for high blood pressure has been proven effective, at least in the study, the researchers still don't know why. Hermida said the effect could be due to the body's internal clock.

This results in the same drug having significant differences in its effect when taken at a different point in time. Hermida dubbed this as "chronotherapy."

"The same antihypertensive medication, the same molecule, at the same dose, ingested at two different times have totally different pharmacokinetics and pharmacodynamics and therefore they behave as two totally different medications," the lead researcher told The Guardian, a British newspaper.


Blood pressure medicines are efficient at night, according to previous research / Photo Credit: Pixabay


Earlier works show that high blood pressure when asleep and the small differences between blood pressure during the day and at night both pose significant risk factors for cardiovascular problems.

Previous research also suggests that taking blood pressure treatments at night increases effectivity and might lead to fewer heart attacks and strokes, The Guardian reports.

These findings are what prompted the researchers to compare the long-term effects of medication intake at night in the Hygia Chronotherapy Trial.

The results of the recent trial could change how blood pressure treatments are prescribed and enhance their effect on patients. However, more work needs to be done—especially in determining why the timing of the medication matters in terms of the effectivity of the drug. This could soon become clear with the results of other major studies.