Studies show p.m. is better, but consistency is more important.
The value of a daily, low-dose aspirin regimen for some people has long been established. But, should you take it in the morning or evening?’
A 2008 study by the Mayo Clinic suggested nighttime consumption of low dose aspirin (81 mg or “baby” aspirin) is preferred over taking it in the morning.
According to the U.S. Centers for Disease Control and Prevention taking a daily dose of aspirin can be useful for someone who has had a heart attack, stroke, angina or peripheral vascular disease or may be at risk for same. However, there are some instances where aspirin may not be appropriate as a daily regimen. Only a discussion with your doctor will determine if you should or should not take daily aspirin.
The recommendation of the American Heart Association is that people at high risk of heart attack take a daily low-dose of aspirin (again, only after consulting your doctor or health care provider) and that heart attack survivors regularly take low-dose aspirin.
But, that still leaves the question of what time of the day to take aspirin if you are taking it daily.
Day Time or Nighttime?
The Mayo Clinic study was conducted not to determine the time of day to take aspirin, but had to do with sufferers of sleep apnea that had a heart attack at night. It was only in that specific circumstance that nighttime use of aspirin was suggested in this study.
In another study in 2011, conducted by scientists in Spain, it was reported that a small dose of aspirin taken at night could reduce the risk of heart attack or stroke in people with high blood pressure – more so than if aspirin were taken in the morning. As reported in many media stories, the researchers determined that aspirin lowers blood pressure to normal for up to 24 hours, but the effect only happens when aspirin is taken at night.
However, on closer inspection of the study itself, the research indicated it was hypertension medication – not necessarily only aspirin – that had the nighttime effect. The researchers had tested more than 660 patients and had some of them take their medication at bedtime and others in the morning. Following up with the patients after more than five years, the researchers found that the patients who took their medicine at night had an adjusted risk for cardiovascular events that was approximately one-third that of patients who took all medications in the morning. Therefore, the researchers concluded that for patients with hypertension taking their medicine at night was better. But, even the researchers acknowledge they could not determine why aspirin or other medications might work better at night (although they surmise it may have something to do with the slower production of hormones or other body substances). And, they admit, timing the best moment to give a drug is an emerging science at this point.