The researchers say that people should consider taking aspirin immediately after having a minor stroke to prevent or reduce the further harm caused by a stroke.
Scientists from the University of Oxford, UK say that although doctors have recommended taking the drug, the benefits of taking it early are “grossly underestimated” and sometimes treatment is late.
Writing in the Lancet medical journal, the researchers call for clearer treatment and guidelines for society.
The National Health Service (NHS) said it would consider the research findings carefully.
Minor strokes and TIAs (transient ischemic attacks or mini-strokes) occur when there is the disruption of blood flow to the brain, which can cause weakness in the legs or a number of problems with speaking or gaze.
These symptoms usually go away within a few days.
However, the chance of having a major stroke, with more permanent symptoms, is higher in the days after a mild stroke.
Previous research has suggested that aspirin plays a role in reducing these symptoms, especially in the long term.
But the team of scientists said their findings suggest most of these benefits were in the first critical hours and days after a mild stroke or TIA.
They estimate that taking aspirin earlier can reduce the risk of having a major stroke, by a ratio of one in 100 people to one in 20 people per day.
Study leader Prof. Peter Rothwell said the benefits of immediate aspirin therapy were “severely underestimated”.
He added, “We need to encourage people, if they think they already have some neurological symptoms that might cause a mild stroke or TIA, to take aspirin immediately, as ideally as seeking medical help.”
The researchers said patients who had mild strokes were not only asked to go home from the emergency department with the recommendation to add aspirin in the next.
But they also called on medical services – including nurses and NHS support services – to recommend drugs as soon as possible if they suspect a patient has a mini-stroke / TIA.
The team reviewed data from 15 tests, which involved thousands of people who had taken aspirin immediately after a stroke or as a long-term treatment to prevent a second stroke.
Dr. Dale Webb, of the charity Stroke Association, described the trial as an interesting development.
He added, “However, it is important to note that taking aspirin is not an alternative to seeking medical attention. Anyone who feels they have had a mini-stroke / TIA should always call 999 as soon as possible.
“And these findings suggest that anyone who has symptoms of a stroke then feels worse while waiting for medical treatment if they are able, can take aspirin.”
Meanwhile, Tony Rudd, National Clinical Director for stroke management at the UK’s NHS, said, “This report contains important data that needs to be carefully considered and then if needed, appropriate changes made to guidelines for managing acute stroke and transient ischemic attacks.”
Health experts recommend that aspirin should not be taken without medical advice in case of bleeding disorders or inflammation and should be considered with caution if a person has asthma, for example.
New stroke management guidelines for doctors will be released soon.