Antiplatelets for stroke and transient ischemic attack (TIA)

Examples

---

Brand Name	Chemical Name
St. Joseph Adult Chewable Aspirin	aspirin

Brand Name	Chemical Name
Aggrenox	aspirin with extended-release dipyridamole

Brand Name	Chemical Name
Plavix	clopidogrel

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:¹

• Reduces the risk of stroke in people who have already had a transient ischemic attack (TIA) or ischemic stroke.
• Can reduce the risk of stroke in those with an irregular heart rhythm (atrial fibrillation) who cannot take warfarin, an anticoagulant.

Aspirin or other antiplatelet drugs may decrease 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 is most often used for people who have had another transient ischemic attack (TIA) or stroke while taking aspirin or for people who cannot take aspirin.

Clopidogrel also may be given to people who are allergic to aspirin and need a medication to prevent the formation of blood clots.

How Well It Works

---

Aspirin reduces the risk of stroke and heart attack or another transient ischemic attack (TIA).¹

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.²

Studies have shown that the combination of aspirin and extended-release dipyridamole reduces the risk of stroke by about 30% and is a safe and effective alternative to aspirin alone.^{3, 4}

Clopidogrel is a safe and effective alternative to aspirin.⁴

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

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.⁵ Higher doses are associated with more side effects, especially bleeding problems.

Safety tips when taking aspirin

Follow these safety tips when taking aspirin.

• Take the medication 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.

The American College of Cardiology and the American Heart Association recommend that short-acting dipyridamole alone not be used by people who have chronic stable angina (an indicator of coronary artery disease) because dipyridamole may reduce blood flow to portions of the heart (ischemia) during exercise.⁶ Extended-release formulations, such as Aggrenox, do not appear to have this risk and may be safe for people with angina. Talk to your doctor if you are considering taking a medicine that contains dipyridamole.

Clopidogrel is commonly used in people who have had a stroke and heart disease. Clopidogrel may be preferred as an alternative to aspirin.⁴

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

References

---

Citations

1. Lip GYH, et al. (2006). Stroke prevention, search date July 2006. Online version of Clinical Evidence (15): 1–27.

2. Warburton E (2006). Stroke management, search date June 2006. Online version of Clinical Evidence (15): 1–15.

3. Sacco R, Elkind M (2000). Update on antiplatelet therapy for stroke prevention. Archives of Internal Medicine, 160(11): 1579–1582.

4. Albers G, et al. (2001). Antithrombotic and thrombolytic therapy for ischemic stroke. Sixth ACCP Consensus Conference on Antithrombotic Therapy. Chest, 119(1, Suppl): 300S–320S.

5. 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.

6. Gibbons RJ, et al. (2002). ACC/AHA 2002 Guideline Update for the Management of Patients With Chronic Stable Angina: A Report of the American College of Cardiology Foundation and the American Heart Association Task Force on Practice Guidelines, p. 50. Available online: http://www.acc.org/qualityandscience/clinical/guidelines/stable/stable_clean.pdf.

Credits

---

Author	Robin Parks, MS
Editor	Kathleen M. Ariss, MS
Associate Editor	Pat Truman
Primary Medical Reviewer	Anne C. Poinier, MD - Internal Medicine
Specialist Medical Reviewer	Richard D. Zorowitz, MD - Physical Medicine and Rehabilitation
Last Updated	March 6, 2007