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- What is aspirin?
- What is aspirin therapy?
- What are the side effects of aspirin?
- What are the latest recommendations on the use of aspirin in the primary prevention of heart (cardiovascular) disease?
- What dosage of aspirin should I take to prevent and treat heart attacks and strokes?
- How effective is aspirin for preventing heart attacks among healthy people?
- Who should take aspirin to prevent and treat heart attacks and strokes?
- Who should not take aspirin to prevent heart attacks and strokes?
- When is aspirin used for preventing and treating heart attacks and strokes?
- Aspirin for treatment of heart attacks
- Aspirin for treatment of exertional and unstable angina
- Aspirin for treatment of ischemic strokes
- What is aspirin allergy?
- What drugs might interact with aspirin?
- What can be done to reduce the risk of ulcers from long-term aspirin use?
- What are the limitations of aspirin treatment?
- What is aspirin resistance?
- What is in the future for the research on aspirin resistance?
What dosage of aspirin should I take to prevent and treat heart attacks and strokes?
An ideal dose of aspirin is one that maximizes its benefits but minimizes side effects. However, the ideal dose of aspirin for primary or secondary prevention of ischemic strokes and heart attacks has not been established firmly.
- In situations where an immediate antiplatelet effect is needed (for example, in the treatment of acute heart attacks, ischemic strokes, and unstable angina) aspirin at moderate doses (160–325 mg/day) will produce rapid and immediate antiplatelet effects. In the ISIS-2 trial, a dose of 160 mg/day given within 24 hours of the onset of symptoms of heart attack was shown to decrease deaths due to heart attacks by 23%. Therefore, this is the dose recommended for acute heart attacks and unstable angina.
- At lower doses, such as 75 mg/d, the antiplatelet effect of aspirin can be achieved in several days instead of minutes. Since the risk of serious bleeding from aspirin is lower at lower doses, 75 mg/d is an appropriate dose for long-term primary and secondary prevention. Even though aspirin at doses as low as 40 mg/d has been shown to have anti-platelet effects, there is insufficient and inconclusive data to show that such low doses are effective in preventing heart attacks and ischemic strokes.
There also is no evidence that higher doses of aspirin, such as 1000 mg/day or higher, is more effective than lower doses. Some studies even suggest that higher doses may not be as effective as lower doses. Since the side effects of aspirin are more frequent with higher doses, doctors generally do not recommend higher doses for long-term use.
How effective is aspirin for preventing heart attacks among healthy people?
Long-term, low dose aspirin (75-160 mg/d) infrequently causes serious side effects; therefore, among people with advanced atherosclerosis (people who already have heart attacks and strokes, patients with angina or TIAs, and patients who need PTCA and coronary artery bypass surgery. The benefits of low dose aspirin usually outweigh the risks of long-term aspirin (discussed in this article).
Unlike the treatment of patients with advanced atherosclerosis, aspirin use among healthy subjects (for example, individuals with no prior heart attacks or strokes) is more controversial. In the U.S. Physicians' Health Study (a study comparing 325 mg of aspirin every other day to placebo among more than 20,000 healthy male doctors), there were fewer heart attacks among aspirin users as compared to placebo users. However, the overall rate of death from heart disease was no different between aspirin users and men on placebo. Furthermore, there is insufficient data to evaluate the benefit of aspirin among healthy women.
Therefore, the potential benefits of long-term aspirin in healthy subjects may not justify the risks of serious side effects of aspirin, including bleeding from ulcers and blood vessels in the brain. Healthy individuals should discuss long-term therapy with aspirin with their doctors before they start taking aspirin.
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