Aspirin has the reputation of being a miracle drug: the white tablet containing the active ingredient acetylsalicylic acid (ASA for short) is a bestseller from the Bayer Group and is swallowed against headaches, fever or inflammation. For a long time, however, physicians also assumed that the blood-thinning agent helps against strokes and can prevent them. That’s why many people take an aspirin pill every day as a preventive measure. However, research is not quite as sure about the effectiveness of this medication. The side effects could potentially do more harm than good in healthy people.
Aspirin for stroke: Helpful – but controversial
Bayer advertises its world-famous drug, which has been on the market for more than 120 years, as “surprisingly versatile”. And in fact, the Deutsches Ärzteblatt describes the active substance ASA as an integral part of the treatment of cardiovascular diseases. Patients who have already suffered a stroke are usually prescribed ASA in a dose of up to 100 mg per day, according to the journal.
Especially in the USA – but also in Germany – the drug is also taken every day as a preventive measure, although no risk of a stroke has yet been identified. Even the United States government-appointed disease prevention experts (USPSTF) had long recommended certain age groups take aspirin daily to reduce the risk of heart attack or stroke. However, only until 2022, after which they withdrew their recommendation. Because different studies in recent years have only been able to prove a benefit for patients who have already had a heart attack or stroke. In addition to positive effects, the active ingredient could also “cause potentially serious damage,” said USPSTF representative John Wong before publicly. And the benefits of the drug are not enough to offset this increased risk.
Aspirin for stroke: what dangerous side effects are possible?
“Because the role of aspirin in primary prevention is unclear, there are sometimes even contrary recommendations,” write Imperial College cardiologist Sean Zheng and King’s College London’s Alistair Roddick in an analysis in the medical journal JAMA. Researchers understand primary prevention to be the prevention of diseases. The potential harm is similar to the potential benefit: taking aspirin daily increases the risk of major bleeding by 0.47 percent. That may not sound like much at first, but the benefit is less: a cardiovascular incident is prevented by just 0.38 percent through the preventive measure.
In addition, aspirin can weaken the body elsewhere: “Aspirin is a drug that inhibits the formation of special proteins in the stomach and in the mucous membrane of the intestine,” explained gastroenterologist Matthias Ebert from the University Hospital Mannheim SWR. These proteins protect the mucous membrane in the intestines and stomach. If this protein is inhibited, it can lead to mucosal injuries and severe bleeding.
Prevent stroke with aspirin: Study results dampen the good reputation
One Study called “Aspree” (Aspirin in Reducing Events in the Elderly) studied the effectiveness of aspirin against cardiovascular disease in the elderly. The average age of the participants – around 19,000 healthy people in the US and Australia – was 74 years. They were divided into a group that took prophylactic aspirin and a placebo group that did not take prophylactic aspirin.
The study ran for around five years before the researchers took stock: The aspirin group did not show a significantly lower risk of cardiovascular disease, but there was a significantly increased risk of bleeding. Mortality in the ASA group was even slightly higher than in the placebo group. Fatal cancer and gastrointestinal tumors were more common among the aspirin participants.
The so-called “Ascent” study from 2018 in the New England Journal of Medicine also produced mixed results. The study analyzed the low-dose intake of aspirin in diabetic patients – who are also at risk of stroke – over a period of seven years. In fact, fewer strokes and other cardiovascular diseases were recorded here – but the number of serious bleedings, for example in the brain or eyes, increased.
Aspirin for stroke: neurological side effects
Also, regular high doses can lead to neurological symptoms like this science magazine spectrum explains: ringing in the ears, headache, blurred vision, drowsiness, dizziness, confusion. The drug can also be dangerous for people with asthma because it increases bronchoconstriction.
Conclusion: Can aspirin prevent a stroke?
Even if ASA is used as a drug for existing cardiovascular diseases and in the therapy after stroke, large-scale studies show no significant benefit for the prevention of stroke – they do show that the damage from heavy bleeding easily outweighs it. Broke in 2014 Japanese physicians their study with around 15,000 participants even ended prematurely, because those who took ASA had hardly fewer heart attacks, but more bleeding. In general, even healthy people should always check with a doctor before taking medication regularly.