Who needs Plavix

Content provided by the Faculty of the Harvard Medical School

Who needs Plavix

This super aspirin is meant mainly for people at high risk of having a heart attack or stroke.

If you have read a magazine or watched television, odds are you've seen an ad about taking Plavix to cut your chances of having a heart attack or stroke. Looking at the hale and hearty models used in these ads, it would be easy to get the impression that Plavix is for everyone.

It isn't. The drug is meant for people in five high-risk groups: those who have had a heart attack or stroke, who have had an artery-opening stent implanted, who have peripheral arterial disease, who have unstable angina (chest pain at rest), or who cannot take aspirin. Others can take Plavix, of course, but it may be more drug than they need, or the possible side effects might outweigh any small benefit.

What it does

Although many factors (high blood pressure, high cholesterol, smoking, stress, lack of activity, et cetera) set the stage for a heart attack or stroke, a blood clot is what usually brings down the curtain. Inside the body, a prime source for a blood clot, or thrombus, is a cholesterol-filled plaque that begins to leak. This triggers the same process that occurs when you cut a finger.

Small fragments of blood cells called platelets kick off clotting. Once platelets are activated by substances in the blood, they stick to each other and to the sides of blood vessels. The ensuing gluey scaffold becomes covered with strands of fibrin, a protein that circulates in the bloodstream, forming a solid patch.

Sealing the crack in a plaque and preventing its contents from oozing into the bloodstream is usually a good thing. Sometimes, though, the clot is so big it blocks blood flow. Or it breaks away and lodges in a smaller vessel downstream. When either of these happens in an artery that nourishes the heart or brain, a heart attack or stroke may follow.

Aspirin blocks one pathway by which platelets are activated to become "sticky." This translates into fewer clots. Since the 1980s, aspirin has been a mainstay for heart attack prevention.

If aspirin is good, researchers wondered, could something else be better? That question eventually led to the discovery of clopidogrel (Plavix), which blocks platelet activation by entirely different routes than aspirin. This difference makes Plavix a bit more powerful than aspirin, as well as a bit easier on the stomach. But it is much harder on the pocketbook. Plavix costs $3–$4 a day, compared with pennies a day for aspirin.

Who needs it?

Large clinical trials are one of the best ways to map the benefits of a new medication. Data from a handful of such trials and other studies are defining when Plavix can be helpful. Note that when the drug is used in combination with aspirin, it is usually best to use low-dose (81 mg) aspirin.

After placement of a stent. Wire mesh stents are great at propping open arteries. They are also fertile breeding grounds for blood clots. Expect to take Plavix for at least one month to a year after getting a stent, depending on which model was implanted. Currently, the American Heart Association recommends that people stay on Plavix for one year if they had a drug-coated stent implanted because this type of stent carries with it a higher chance of blood clots than bare metal stents.

During a heart attack or unstable angina. In many medical centers, emergency treatment of serious chest pain (acute coronary syndrome) includes Plavix along with aspirin. In one major study, the combination was 20% better at preventing a repeat heart attack, stroke, or cardiovascular-related death than aspirin alone (9.3% vs. 11.4%).

There's one drawback of using Plavix during an episode of serious chest pain. President Clinton discovered it in 2004. The drug is such a powerful antiplatelet agent that if you need bypass surgery, you'll have to wait for a few days until it wears off.

Plavix is usually recommended for 9–12 months after an episode of intense chest pain at rest.

After a heart attack. Taking Plavix alone after a heart attack offers small but significant extra protection from cardiovascular problems compared with aspirin. What if you had a heart attack two or three years ago? If everything is fine, you probably don't need this medication. But if you have increasing chest pain with activity (angina) or blockages in several arteries, your doctor might want you to stay on Plavix indefinitely.

After a stroke. Aspirin alone or Plavix alone after a stroke can reduce the chances of having a repeat stroke or a heart attack. Taking both isn't much better and leads to more bleeding problems.

After a mini-stroke. Like seismic rumbles before an earthquake, a transient ischemic attack, or TIA, often precedes a full-blown stroke. Many doctors recommend taking Plavix plus aspirin for three months, and then one or the other after that.

With peripheral arterial disease. Narrowing of arteries in the legs can cause pain when walking and increases the risk of having a heart attack or stroke. Plavix, alone or in combination with aspirin, can help lower this risk.

When aspirin isn't an option. If you are at high risk for a heart attack or stroke, but aspirin triggers an allergic reaction, doesn't affect your platelets, or wreaks havoc with your stomach, Plavix may be a viable alternative.

Balancing risks and benefits

Plavix is not a miracle cure. In some situations it is a bit better than aspirin; in others it's of equal benefit.

Like every drug, Plavix has side effects. Some are merely aggravating, but others are dangerous. About 1 in 20 people who takes the drug experiences itching, rash, or diarrhea. It upsets the stomach almost as much as aspirin and can cause serious bleeding. A small number of people taking Plavix have developed a potentially deadly condition called thrombotic thrombocytopenic purpura, which is characterized by low levels of platelets and red cells in the bloodstream.

Plavix isn't for everyone. There are two main reasons for this. The drug has virtually the same benefits as aspirin and a similar side effect profile. Yet it costs about 100 times more than aspirin. Because Plavix has not been tested in people who are at low risk for a heart attack or stroke, we don't know its benefit-to-risk balance for them.

If a Plavix ad gets you to talk with your doctor about your heart and health, great. But don't expect to come away from the conversation with a Plavix prescription if you are relatively healthy and at low to moderate risk of heart disease or stroke.

E-mail This | Print This

Last updated:	May 11, 2007