Plavix isn't for everyone

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Plavix isn't for everyone

Adding Plavix to aspirin doesn’t help people without heart disease.

There are several good reasons to fortify aspirin’s anti-clotting action with the “superaspirin” Plavix (clopidogrel). Having stable heart disease or being at high risk for developing heart disease, it turns out, aren’t among them. Surprising results from a trial that included more than 15,000 volunteers showed that aspirin alone is safer and just as effective as aspirin plus Plavix at preventing heart attack, stroke, and other cardiovascular problems in these groups.

These findings don’t diminish the benefits of Plavix plus aspirin, or Plavix alone, in some situations. It remains an important treatment for people

• who have recently had a heart attack

• with unstable angina (chest pain at rest)

• who have just undergone artery-opening angioplasty, especially with the placement of a wire-mesh stent

• with peripheral artery disease.

Could the combination also help people with stable, run-of-the-mill, cholesterol-clogged arteries in the heart, brain, or elsewhere? To answer that question, researchers started the Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management, and Avoidance (CHARISMA) trial. It was the next logical step in Plavix research. It was also an important one, since more and more people not covered by earlier clinical trials were taking Plavix, prompted in part by ads on television and in magazines.

In CHARISMA, half of the 15,603 volunteers took aspirin plus Plavix while the other half took aspirin plus a placebo. After two years, the proportions of volunteers who had suffered a heart attack or stroke or died of a cardiovascular cause were virtually the same in both groups: 6.8% for Plavix plus aspirin and 7.3% for aspirin alone. The rate of moderate to severe bleeding complications, though, was higher with Plavix plus aspirin. In the study as a whole, the researchers estimated that for every 94 cardiovascular “events” prevented by Plavix plus aspirin, the combination caused 93 cases of bleeding serious enough to require a transfusion.

The hazards of Plavix plus aspirin outweighed the benefits in people who didn’t have diagnosed heart disease but who were at high risk for it due to diabetes, narrowed arteries in the neck, or poor blood flow to the legs. The reverse — a tip of the scales toward benefits over risk — was seen in people who had already developed heart disease, such as heart attack or stroke survivors or those with angina or peripheral artery disease.

Setting limits

The CHARISMA results don’t tarnish the reputation of Plavix. Plavix and aspirin block different pathways by which platelets become “sticky.” Because platelets kick off the clotting process, and clots cause heart attacks, both drugs prevent this feared problem — and save lives — in people whose arteries are likely to generate blood clots.

Plavix is an important addition to aspirin if you have recently had a heart attack or have unstable angina (chest pain at rest) or peripheral artery disease. If you have recently received an artery-opening stent, keep taking Plavix until your doctor says to stop — the chances of clotting inside a stent are as much as 90 times higher without Plavix.

But the CHARISMA results should put the brakes on the use of Plavix in other groups. If you haven’t been diagnosed with heart disease or had a cardiovascular problem caused by a blood clot, but are “merely” at high risk for developing heart disease, then Plavix plus aspirin might do you more harm than good.

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Last updated:	August 21, 2006