Mixed Results for Plavix-Aspirin Combo

Stroke recurrence may be reduced by blood thinner and aspirin but studies are conflicting

/ Author:  / Reviewed by: Robert Carlson, M.D

(RxWiki News) The blood thinners clopidogrel (Plavix) and aspirin both help save lives of heart patients by preventing clots. When used together, however, results have been mixed.

Clopidogrel and aspirin are both anti-clotting agents that prevent platelets (small particles in the blood) from sticking together.

One new study showed that taking clopidogrel and aspirin together reduced the risk of a second stroke in stroke patients.

Other research found that a clopidogrel-aspirin combo was unlikely to prevent recurrent strokes and could even increase the risk of death.

"Consult a pharmacist about taking clopidogrel with aspirin."

S. Claiborne Johnston, MD, professor of neurology and director of the Stroke Service at the University of California San Francisco, was senior author of a study that found that adding a second drug to aspirin therapy lowered the risk of a second stroke in the weeks after a clot caused minor stroke.

The second drug, clopidogrel, has been especially effective in inhibiting clots in patients who have implanted stents (mesh tubes that keep blood vessels open).

Dr. Johnston and his colleagues based their report on 5,174 patients with minor, clot-caused strokes from 114 centers in China. Patients had a median age of 62 and 34 percent were women. They were all participants in the Clopidogrel in High-risk patients with Acute Non-disabling Cerebrovascular Events (CHANCE) study.

These mini-strokes are called transient ischemic attacks (TIAs). They happen when a blood clot temporarily clogs an artery and blocks blood flow to the brain.

Within 24 hours of a TIA, patients started treatment with either low-dose aspirin plus a placebo or the same aspirin regimen plus clopidogrel.

During the 90 days after treatment began, 8.2 percent of patients in the dual therapy group experienced another stroke, while 11.7 percent in the aspirin-only group had another stroke.

As far as side effects are concerned, seven patients (0.3 percent) in the dual therapy group and eight (0.3 percent) in the aspirin-only group had moderate or severe bleeding.

“TIAs and minor strokes are emergencies,” said Dr. Johnston. “If we start dual treatment early, it looks like we can reduce the risk of another stroke by more than 30 percent.”

In comparison, aspirin therapy alone cut stroke risk by about 20 percent, he said.

Yongjun Wang, MD, study principal investigator, professor of neurology and vice-president of Beijing TianTan Hospital, Capital Medical University in Beijing, China, warned that while the results reflected response in Chinese patients, they may not apply to other populations.

“In China, stroke and mini-stroke patients are six to eight years younger on average than Americans, and there are different genetic variations that have an impact on the metabolism of clopidogrel,” said Dr. Wang.

Other studies seemed to contradict the benefits of taking aspirin and clopidogrel together. Last year, at the 2012 American Stroke Association’s International Stroke Conference, researchers from Canada’s University of British Columbia in Vancouver presented a study finding that adding clopidogrel to aspirin treatment was unlikely to prevent recurrent strokes and may increase the risk of bleeding and death in patients with stroke.

Clopidogrel is now sold in a generic form, which is much more affordable than the previously branded product. The generic form of the drug can be bought for as little as $37 a month compared to $200 when it was non-generic.

The study by Dr. Johnston was presented in February at the American Stroke Association’s International Stroke Conference 2013. The Ministry of Science and Technology of the People’s Republic of China funded the research. All findings are considered preliminary until published in a peer-reviewed journal.

Reviewed by: 
Review Date: 
February 12, 2013
Last Updated:
February 15, 2013