From the Guidelines
After a stroke, the recommended aspirin dosing is typically at least 160 mg given immediately as a one-time loading dose, followed by 81-325 mg daily for long-term secondary prevention. This regimen should be started after brain imaging has excluded intracranial hemorrhage and after dysphagia screening has been performed and passed 1. The initial higher dose helps quickly establish platelet inhibition, while the lower maintenance dose reduces bleeding risk while maintaining effectiveness. Patients should take aspirin with food to minimize gastrointestinal irritation. This antiplatelet therapy works by inhibiting thromboxane A2 production, preventing platelet aggregation and reducing the risk of recurrent stroke. Some patients may be prescribed dual antiplatelet therapy (aspirin plus clopidogrel) for a limited time, particularly after minor strokes or TIAs, but this decision should be made by a healthcare provider 1.
Key considerations for aspirin dosing after a stroke include:
- Starting with a loading dose of at least 160 mg as soon as possible after stroke onset, provided there are no contraindications such as intracranial hemorrhage 1
- Continuing with a daily dose of 81-325 mg for long-term secondary prevention 1
- Considering dual antiplatelet therapy with clopidogrel for high-risk patients or those with minor strokes of noncardioembolic origin, but only for a limited duration of 21-30 days 1
- Being aware of the potential for bleeding complications and monitoring patients accordingly 1
It's also important to note that the evidence from the Canadian Stroke Best Practice Recommendations 1 is more recent and of higher quality compared to other studies, such as the American College of Chest Physicians evidence-based clinical practice guidelines 1. Therefore, the recommendations from the Canadian Stroke Best Practice Recommendations should be prioritized when making decisions about aspirin dosing after a stroke.
From the Research
Aspirin Dosing After a Stroke
- The appropriate dose of aspirin for the primary and secondary prevention of stroke is not well established, but studies suggest that 160 mg/day is effective in preventing recurrent stroke or death 2.
- In patients with a history of stroke or transient ischemic attack (TIA), 50 mg/day has been shown to be effective in men and women 2.
- The risk of major bleeding with 160 mg/day is the same as with 80 mg/day: 1 to 2 cases per 1000 patient years of treatment, and the risk of fatal bleeding is the same with 80 and 160 mg/day 2.
- Low doses of aspirin (50-100 mg/day) are recommended for long-term stroke prevention in patients with noncardioembolic stroke or TIA, and the combination of aspirin and extended-release dipyridamole is recommended over aspirin alone 3.
Comparison of Aspirin Doses
- Studies have compared the efficacy and safety of different aspirin doses, and the results suggest that low doses (50-100 mg/day) are as effective as high doses, but are better tolerated in terms of gastrointestinal side effects 4.
- The combination of aspirin and clopidogrel is more effective than aspirin alone in reducing the risk of recurrent stroke, but increases the risk of major bleeding events 5.
Antiplatelet Therapy
- Antiplatelet therapy has an essential role in the management of ischemic stroke, and the specific antiplatelet regimen should be individualized based on the stroke characteristics, time from symptom onset, and patient-specific predisposition to develop hemorrhagic complications 6.
- Dual antiplatelet therapy with aspirin and clopidogrel is superior to antiplatelet monotherapy in secondary stroke prevention when used in patients with mild noncardioembolic stroke or high-risk transient ischemic attack, but is associated with an increased risk of major bleeding 6.