Why taking blood pressure tablets at bedtime could prevent an early death

Henrietta Strickland
October 25, 2019

Taking blood pressure medications at bedtime rather than in the morning almost halves the risk of dying from a heart attack, stroke or heart failure, a large, new study finds.

The researchers, who are part of the Hygia Project led by professor Ramón C. Hermida, PhD, director of the Bioengineering and Chronobiology Labs at the University of Vigo, Spain, found that patients who took their medication at bedtime had almost half the risk (45% reduction) of dying from or suffering heart attacks, myocardial infarction, stroke, heart failure, or requiring a procedure to unblock narrowed arteries (coronary revascularization), compared to patients who took their medication on waking.

The upshot, he said, was that the same drug could have vastly different effects if taken at a different point in time, something that has been dubbed "chronotherapy".

To achieve compliance, it's important to stick to a routine, Bhusri said.

Unfortunately, it often takes people too long to know they have high blood pressure.

Besides the effect on blood pressure, the team found those who took the medication at bedtime also showed better kidney function and cholesterol measures, both of which are important factors when it comes to cardiovascular disease. Now the Hygia Project is investigating what a person's BP should be while asleep.

The patients who followed for an average of around six years.

"This study has the potential to transform how we prescribe blood pressure medication", he said.. At least once a year, participants also wore a mobile monitor, which logged multiple blood pressure readings over two days. Total events: Death from all causes, myocardial infarction, coronary revascularization, heart failure, ischemic and hemorrhagic stroke, angina pectoris, peripheral artery disease, thrombotic occlusion of the retinal artery, and transient ischemic attack.

The researchers, including those from the University of Vigo in Spain, found that in participants taking their medication just before hitting the sack at night, the risk of death from heart or blood vessel problems was reduced by 66 per cent, the risk of myocardial infarction by 44 per cent, coronary revascularisation by 40 per cent, heart failure by 42 per cent, and stroke by almost 50 per cent.

Overall, the reduction in risk for cardiovascular-related death was 45 percent, the findings showed.

"It could be that dosing at bedtime is the only way you can control that surge in the first couple of hours when you wake up", Muldoon said. This is true whether daytime measurements taken at the doctor's office are normal or elevated.

The patients were then followed for between four and eight years, with blood pressure measured over a 48-hour period at the outset and at least once a year during the study.

Hermida did acknowledge a few caveats.

The scientists stress the participants all slept at night time, therefore it is unclear if the same results would occur among shift workers. That means the study can not speak to how medication routines might affect individuals who habitually work at night. All the participants were also white and of Spanish descent.

"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", said Hermida. According to the research, after analyzing 19,000 blood pressure patients, the results are declared.

"Importantly, this is a "real world" study where doctors were allowed to prescribe whatever they wanted and just change medication timing".

Vanessa Smith, senior cardiac nurse at the British Heart Foundation (BHF), said the study supported previous evidence but further research was needed.

There's more about blood pressure medications at the American Heart Association.

Other reports by Click Lancashire

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