Bedtime Aspirin May Keep Heart Attack Away

Heart attack risk in the morning may be lowered by taking an aspirin at night

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Most heart attacks happen in the morning. For some, a daily low-dose of aspirin may lower this risk. While many take aspirin in the morning, it may be more effective if taken at bedtime.

The American Heart Association recommends that people at high risk of heart attack and heart attack survivors regularly take low-dose aspirin (if told to do so by their healthcare provider). Aspirin thins the blood and helps prevent clotting.

New research suggests that the best time to take aspirin for heart therapy may be right before going to sleep at night.

"Talk to your doctor about low-dose aspirin to prevent heart attack."

Tobias Bonten, MD, from the Department of Clinical Epidemiology at Leiden University Medical Center in The Netherlands, and colleagues discovered that a sign of higher heart risk was reduced in patients who took aspirin at night compared to those who took it in the morning.

From a group of 290 patients with previous cardiovascular disease, patients were randomly selected to receive either 100 milligrams of aspirin upon waking or at bedtime over the course of two three-month periods.

At the end of each treatment period, blood pressure was recorded and platelet reactivity was measured.

Platelets are specialized disk-shaped cells in the bloodstream that are involved in the formation of blood clots and play an important role in heart attacks and strokes. Platelets can detect a disruption in the lining of a blood vessel and react to build a wall to stop bleeding.

Higher platelet activity contributes to a higher risk of acute heart events, according to Dr. Bonten.

From their study, Dr. Bonten and colleagues noted that platelet activity was reduced by 22 aspirin reaction units (as measured by the VerifyNow Aspirin assay) in the group taking bedtime aspirin compared to the morning aspirin-taking group. Values that show therapeutic benefit of aspirin are in the range of 350-549 ARU (aspirin reaction units), according to VerifyNow. Any ARU reading of 550 and higher is in the non-therapeutic range.

“We know that aspirin works so well to prevent cardiovascular diseases because it inhibits blood platelets. However, these blood platelets are more active during morning hours, when the most heart attacks and strokes also happen," Dr. Bonten told dailyRx News.

"Although we did not look at the actual occurrence of heart disease and strokes during the morning hours, we think that taking aspirin at bedtime could potentially reduce the occurrence of these diseases during the morning hours. A confirmation of this hypothesis still has to be confirmed by future research,” Dr. Bonten said.

Although blood pressure was not reduced in this study, the authors pointed out that recent investigations of subjects with mild hypertension showed that aspirin intake at bedtime may significantly decrease blood pressure compared with intake on awakening.

“This study is of major interest to millions of patients worldwide taking low-dose aspirin on a daily basis,” the authors wrote. “If switching to intake of aspirin at bedtime reduces blood pressure and morning peak of platelet reactivity, simply changing this time of intake could make the use of this drug even more effective in preventing recurrent [cardiovascular disease] without any additional costs.”

In additional comments to dailyRx News, Dr. Bonten said, “We found that the adverse effects of aspirin [mostly stomach pain] did not increase when aspirin was taken at bedtime, compared with on awakening. So it seems safe with respect to these side effects to take aspirin at bedtime.”

An abstract for this study was presented at the American Heart Association Scientific Sessions in November. The entire study is still under review of a major medical journal and not yet published.

Review Date: 
November 22, 2013
Last Updated:
November 25, 2013