Ask An Expert: Aspirin and Clopidogrel

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Ask An Expert: Aspirin and Clopidogrel

Question:

Can aspirin and clopidogrel be prescribed together in a patient with coronary disease?

Answer:

Aspirin and clopidogrel can be prescribed together, and often are. This combination is used routinely after angioplasty and stent placement to treat blockages in coronary arteries. However, combining these two drugs does increase the risk of unwanted bleeding.

Aspirin and clopidogrel decrease blood clot formation in different ways. Both affect the platelets (the little cells that help blood clots get started), but they act via different mechanisms. The result is stronger blood-thinning ability than is possible with either drug alone. The bad news is that patients' risk of bleeding is greater than with either drug alone.

The key question for patient and physician is whether the greater effect from the combination is worth the greater risk. To prevent repeat blockage after angioplasty, it is usually worth the risk.

However, this may not be true for other situations. For example, the combination of aspirin and clopidogrel in patients at high risk of stroke has not been shown to be more effective than clopidogrel alone; yet the combination has been shown to increase major bleeding.

The most recent major study of aspirin combined with clopidogrel was called CHARISMA and was published in the New England Journal of Medicine in April 2006. It concluded that "there was a suggestion of benefit with clopidogrel treatment in patients with symptomatic atherothrombosis and a suggestion of harm in patients with multiple risk factors. Overall, clopidogrel plus aspirin was not significantly more effective than aspirin alone in reducing the rate of myocardial infarction, stroke, or death from cardiovascular causes."

The bottom line: There are probably some patients with a very high risk of blood clots who are better off if they take the combination, but for many patients there are increased risks and uncertain benefits.

Thomas Lee, M.D., is the chief executive officer for Partners Community HealthCare Inc. He is a professor of medicine at Harvard Medical School. He is an internist and cardiologist at Brigham and Women's Hospital. Dr. Lee is the chairman of the Cardiovascular Measurement Assessment Panel of the National Committee for Quality Assurance.

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Last updated:	January 24, 2007