Aspirin Might Well Be Considered The Top Utility Player In The Medicine Cabinet
Posted By: News-Medical in Pharmaceutical News

Published: Friday, 8-Oct-2004

Aspirin might well be considered the top utility player in the medicine cabinet. This
cheap over-the-counter drug can be used not only for fever, pain and arthritis, but to
prevent heart attack, stroke or angina. It also may reduce the risk of colorectal
cancer. Yet aspirin also has side effects worth considering, and its very accessibility
may hamper its use.

Aspirin’s anti-clotting and anti-inflammatory abilities protect the heart and blood
vessels. The U.S. Preventive Services Task Force "found good evidence that
aspirin decreases the incidence of coronary heart disease in adults who are at
increased risk for heart disease," and "strongly recommends that clinicians discuss
aspirin chemoprevention with adults who are at increased risk for coronary artery
disease."

Aspirin’s value and potential hazards come from the same source: its ability to
prevent the cells in the blood called platelets from clotting. Yet this deceptively
simple pill demands caution as well. Aspirin can cause potentially dangerous
bleeding in the stomach or brain, but is underprescribed to patients who need it.
The USPSTF estimates that of 1,000 people taking aspirin for five years, about two
to four middle-aged people, or four to 12 older people, will develop gastrointestinal
bleeding and one will have a hemorrhagic (bleeding) stroke.

Facts:

Aspirin treatment for primary prevention of heart attacks is safe and worthwhile if
the benefits outweigh the risks. When an individual’s risk of a coronary event drops
to 0.5 percent a year, the side effects outweigh the benefits to the heart. Physicians
can use several simple scales to measure absolute coronary event risk and then
help patients decide if aspirin is appropriate therapy.

A meta-analysis of 16 clinical trials covering 55,462 patients treated for an average
of 3 years indicates that aspirin reduces risks of heart attack and ischemic stroke
more than it increases the risk of bleeding strokes. Aspirin use prevented 137 heart
attacks and 39 strokes for every 10,000 persons taking the drug, with an increase of
12 bleeding strokes.

Both alcohol and aspirin contribute to gastrointestinal bleeding, but the combination
— an aspirin tablet every other day plus three alcoholic drinks a day — increases
the chance of bleeding sevenfold. Ibuprofen users who are heavy drinkers also are
at increased risk of gastrointestinal bleeding.

One preliminary study indicates that taking aspirin reduces the risk of some types of
breast cancers but not others.

People who have asthma, uncontrolled high blood pressure, severe liver or kidney
disease, bleeding disorders or an allergy to aspirin should not take the drug.

A recent study of 987,000 people has found no association between aspirin and
pancreatic cancer, as had been feared earlier. A preliminary study has shown a
decrease in Hodgkin’s lymphoma among users of aspirin. Such studies are
suggestive and would need to be confirmed before serving as the basis of
recommendations for action.

Researchers are investigating any protective role for aspirin in preventing other
cancers, Parkinson's disease, cognitive decline or dementia.

The Food & Drug Administration cautions: "Only a doctor can tell you whether the
risks of long-term aspirin use may be greater than the benefits."

The big questions facing researchers now are: whether higher doses of aspirin offer
higher benefits, whether some people somehow don’t respond to aspirin and
whether an apparent reduction in cognitive decline seen in self-selected people who
take aspirin can be reproduced in randomized controlled trials.

Multi-Tasking Tablets

Aspirin is potentially helpful to two types of patients: those who have had a heart
attack and those who are at risk. Trying to stop a second heart attack or stroke is
called secondary prevention, but between 20 percent and 30 percent of heart attack
survivors don’t take aspirin, despite national guidelines.

Furthermore, less than half of those who have never had an attack but who are at
risk take aspirin, says Charles H. Hennekens, M.D., of the University of Miami and
Florida Atlantic University. Hennekens recommends aspirin for anyone with a 10
percent chance of a heart attack in the next 10 years. The U.S. Preventive Services
Task Force calls for it if the risk is 6 percent. An online risk assessment calculator is
available at http://hin.nhlbi.nih.gov/atpiii/calculator.asp?usertype=pub.

Paradoxically, aspirin is underused in part because it is cheap and so available.
"Aspirin lies outside the usual medical culture," Hennekens says. "If it were half as
effective, 10 times as expensive and required a prescription, doctors would
probably prescribe it more often."

Unlike other anticoagulants, aspirin doesn’t require monitoring, which undercuts the
drug’s stature.

"Aspirin is perceived as a ‘trivial’ drug, one that doesn’t carry a lot of weight as a
preventive measure," says University of Iowa psychologist Alan Christensen, Ph.D.,
a patient compliance expert. "Because aspirin is an over-the-counter drug, patients
can start or stop taking it at will."

A second problem occurs when well-meaning patients take other drugs like
acetaminophen or ibuprofen instead of aspirin. These painkillers may work well for
headache or muscle discomfort but lack the ability to prevent platelet clotting.

Analysis of the Nurses Health study found that taking aspirin at least twice a week
is associated with a 25 percent reduction in risk for colorectal polyps, the precursors
to colorectal cancer. Nurses who used more than 14 aspirin tablets a week reduced
their risk by half. Other studies have shown similar benefits in men.

Because a greater benefit was shown among those who took higher daily doses,
study author Andrew T. Chan, M.D., of Massachusetts General Hospital cautions,
the next step is to make aspirin safer, or to pinpoint who will get enough protective
benefits to outweigh the risks.

The evidence is not strong enough to recommend aspirin as a preventive measure
for colorectal cancer, Chan says. Colonoscopy and sigmoidoscopy are still the most
effective ways to prevent that cancer.

But people should not take aspirin regularly without consulting a doctor.

"This is a long-term decision and should be made ... between doctor and patient,"
Hennekens says. "Patients should be aware of the benefits and the possible risks."

Each month, the Health Behavior News Service of the Center for the Advancement
of Health brings you Facts of Life: Issue Briefing for Health Reporters, a free
publication that provides background on topics within health and behavior as well
as names of prominent researchers and physicians willing to be interviewed.

Health Behavior News Service
http://www.hbns.org

SOURCE: News-Medical.net, World
http://www.news-medical.net/?id=5417

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