Is Aspirin Safe?

For many consumers, recent research has elevated aspirin’s
status from that of a simple pain reliever to that of a
potential wonder drug.

Some scientists say it may be able to prevent everything
from heart attack and stroke to cataracts, gallstones and
sickle-cell anemia.

But don’t rush to your medicine chest just yet. For every
study showing that aspirin might have newfound benefits,
there’s another showing new risks. Pregnant women are
advised to avoid it altogether. The Food and Drug
Administration (FDA) may order manufacturers to add
cautionary labels to the drug, warning consumers not to
give it to children with fevers because of its
association — widely noted but still
unproven — with potentially fatal Reye’s syndrome.

Like all drugs, aspirin is a double-edged sword, and today
both edges cut deeper than ever before.

Aspirin Heart-Attack Prevention?

Aspirin has been used for thousands of years, but only
recently have scientists learned how it works at the
cellular level. In 1971, aspirin was shown to inhibit
production of prostaglandins, a family of hormonelike
substances found throughout the body. Prostaglandins are
associated with pain, inflammation and menstrual
problems, hence aspirin’s ability to alleviate pain,
inflammation and mild menstrual cramps.

But it’s been the suggestion that aspirin may be useful in
preventing heart attacks that has thrust the drug into the
medical limelight. In a half-dozen studies from 1974
through 1980, more than 10,000 people who had had one heart
attack took aspirin to see if it could significantly reduce
their risk of another. Half the participants took one to
five aspirin tablets a day for up to three years. The rest
took a placebo. In all but one study, the aspirin users
suffered fewer cardiac problems, including heart attacks,
and had a lower overall death rate than those who took the
placebo. But the differences between the two groups were
not statistically significant. Furthermore, the largest
study’s findings took everyone by surprise and raised some
disturbing questions.

That trial was the $7 million AMIS study (Aspirin
Myocardial Infarction Study) sponsored by the National
Heart, Lung and Blood Institute. Every participant in this
double-blind study had had at least one heart attack. Half
took the equivalent of one extra-strength aspirin tablet a
day. The rest took a placebo. At the end of the three-year
study, the aspirin group showed 22 percent fewer nonfatal heart
attacks, but their total overall mortality rate was
actually higher. Why? No one knows. The aspirin users
reported twice as many cases of nausea, vomiting,
constipation and peptic ulcers as the placebo takers. The
reduction in heart-attack risk was not statistically
significant. In fact, the only thing the AMIS project
demonstrated conclusively was the all-too-familiar link
between aspirin and gastrointestinal problems.

To find out “once and for all” if aspirin reduces risk of
heart attack, Harvard Medical School has launched a new
four-year double-blind study involving physicians
themselves as the subjects. So far, 30,000 healthy
physicians over 40 have enrolled. The idea is to see if
aspirin can prevent first heart attacks and strokes in
people who do not have cardiovascular disease. The study,
the most ambitious of its kind ever attempted, should yield
a wealth of information in the late 1980’s — if the
doctors remember to take their medicine.

Aspirin During Pregnancy

Anyone who watches TV knows that aspirin can upset the
stomach, aggravate ulcers and cause other gastrointestinal
problems. But, like many drugs, its most hazardous side
effects occur when it is used by pregnant women. An
estimated two-thirds of all pregnant women use aspirin.
Animal studies leave little doubt that aspirin can cause
birth defects, but human studies are more ambiguous.
Several European studies have implicated the drug as a
cause of infant malformation, including one Finnish study
that showed that mothers of infants with cleft palates had
taken three times as much aspirin during pregnancy as
mothers who gave birth to normal infants. But other
research, including the large American Perinatal
Collaborative Project, has shown no link between aspirin
and any birth defects. At this writing, it’s impossible to
state definitively if aspirin causes human birth defects,
but caution is certainly advised.

Aspirin and the Immune System

Aspirin appears to reduce the effectiveness of interferon,
the body’s natural antiviral protein. Laboratory studies
show that when living cells are bathed in an aspirin
solution, they promptly lose their ability to use
interferon, and are killed by invading viruses. In these
experiments, aspirin reduced the antiviral effect of
interferon by a factor of 1,000. This finding means that
people who take aspirin for colds may prolong the life of
the cold virus and spread their colds to more people.

Aspirin may also cause a temporary but dramatic decrease in
serum complement, a family of proteins necessary to defend
successfully against viruses and bacteria. Healthy
individuals, apparently, can cope with this temporary loss
of protection, but some doctors worry about aspirin use by
people already deficient in serum complement because of
ongoing or recent infection.

Aspirin and other antipros-taglandins may also interfere
with the immune system’s ability to distinguish between
disease agents and the body’s own cells. Aspirin seems to
interfere with the activity of suppressor T lymphocytes,
which normally check excess antibody production. Nobody
knows whether this possible action of aspirin may trigger
such autoimmune disorders as Guillain-Barré syndrome
or multiple sclerosis; however, quite a few cases of
Guillain-Barré followed the U.S. swine-flu
immunization program a few years ago. Did those who
developed Guillain-Barré take aspirin to relieve the
muscle soreness associated with their flu shots? Nobody
knows. But a strikingly similar pattern links aspirin use
by feverish children to Reye’s syndrome. At present, there
is no hard evidence that aspirin-related decreases in viral
defenses do any harm.

But the implications of all the new research into the
drug’s effects are clear: Aspirin is not for everyone. It
clearly provides relief from pain and inflammation. It may
reduce risk of cardiovascular disease. Recent reports have
suggested that it may be of value in the management of
cataracts, sickle-cell anemia, gallstones and food
allergies. And if aspirin is used cautiously and only when
appropriate, it will probably remain a reasonably safe way
to deal with some of life’s more painful moments.

But for each of its many benefits, aspirin can also do harm
when used by the wrong person at the wrong time.