Examples

How It Works

Aspirin is an antiplatelet medicine that decreases blood clot formation by preventing the smallest blood cells (platelets) from sticking together and forming blood clots.

Aspirin with extended-release dipyridamole is used to prevent a second ischemic stroke or transient ischemic attack (TIA).

Why It Is Used

Aspirin is the most commonly used medicine to prevent stroke. Aspirin reduces the risk of stroke in people who have already had a transient ischemic attack (TIA) or ischemic stroke.

Aspirin or other antiplatelet drugs may reduce the risk of stroke in people who cannot have surgery to reopen a blocked carotid artery (carotid endarterectomy).

Aspirin with extended-release dipyridamole (Aggrenox) is used to reduce the risk of additional strokes or TIAs in people who had a stroke or TIA while taking aspirin.

Clopidogrel may be taken with aspirin or instead of aspirin. You might take clopidogrel instead of aspirin if you are allergic to aspirin or if you cannot take aspirin for some other reason. Or you might take clopidogrel instead of aspirin if you have had another transient ischemic attack (TIA) or stroke while taking aspirin. When aspirin and clopidogrel are used together, they may reduce the risk for stroke more than aspirin alone. But this combination is also more likely to cause bleeding than aspirin alone.

How Well It Works

Aspirin reduces the risk of stroke and heart attack or another transient ischemic attack (TIA).

Aspirin reduces the risk of death and dependence due to disability and increases the chance of recovery when it is given within 48 hours of an ischemic stroke that has been confirmed by a computed tomography (CT) scan to rule out hemorrhagic stroke.¹

Studies have shown that the combination of aspirin and extended-release dipyridamole reduces the risk of stroke and is a safe and effective alternative to aspirin alone.^{2, 3}

Clopidogrel is a safe and effective alternative to aspirin.³ And taking both clopidogrel and aspirin may lower the risk of stroke for people with atrial fibrillation. But this combination is more likely to cause bleeding than taking clopidogrel alone or aspirin alone.

It is important for each person to work with his or her doctor to find the best medicine.

Side Effects

Side effects of aspirin include:

• Skin bruising, especially in older people.
• Irritation of the stomach lining.
• Bleeding from the digestive system.
• Allergic reaction.
• Bleeding (hemorrhage) in the brain (rare) or other internal organs of the body.

Side effects of aspirin with extended-release dipyridamole include headache, dizziness, stomach upset, vomiting, and diarrhea.

Common side effects of clopidogrel include:

• Nausea and vomiting.
• Diarrhea.
• Skin rash, itching.

In rare cases, clopidogrel has been associated with a syndrome that resembles a serious bleeding disorder (thrombocytopenic purpura).

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

A large study showed that aspirin in doses of 75 to 150 mg daily is as effective as higher doses for long-term treatment.⁴

Safety tips when taking aspirin

Follow these safety tips when taking aspirin.

• Take the medicine at the same time each day.
• Take aspirin with food to prevent irritation of the stomach.
• Use buffered or enteric-coated aspirin.
• Check with your doctor before using other nonprescription drugs that contain aspirin.
• Be on the alert for signs of bleeding, and call your doctor immediately if any signs occur.
• Let your doctor know if you are taking aspirin and you are planning to have surgery. You may have to stop the aspirin temporarily.

Aspirin with extended-release dipyridamole is more expensive than aspirin alone.

There are no adequate studies on the safety of using dipyridamole during pregnancy.

Clopidogrel is commonly used in people who have had a stroke and heart disease. Clopidogrel may be preferred as an alternative to aspirin.

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.

References

Citations

1. Warburton E (2007). Stroke management, search date May 2006. Online version of BMJ Clinical Evidence. Also available online: http://www.clinicalevidence.com.
2. Lip GYH, Kalra L (2007). Stroke prevention, search date September 2006. Online version of BMJ Clinical Evidence. Also available online: http://www.clinicalevidence.com.
3. Sacco RL, et al. (2008). Aspirin and extended-release dipyridamole versus clopidogrel for recurrent stroke. New England Journal of Medicine, 359(12): 1238–1251.
4. Antithrombotic Trialists' Collaboration (2002). Collaborative meta-analysis of randomised trials of antiplatelet therapy for prevention of death, myocardial infarction, and stroke in high-risk patients. BMJ, 324(7329): 71–86.