Just What the Doctor Ordered? : Health: Research into aspirin’s preventive powers shows it may have positive effects on myriad ailments.
The doctor’s old standby--"take two aspirin and call me in the morning"--could soon be replaced by a new recommendation.
How about: “Take an aspirin daily and don’t call unless you’re sick.”
In the past nine months, researchers have declared that the inexpensive, readily available drug can dramatically reduce the risk of heart attack and a particular type of stroke. And aspirin’s preventive powers may not end there.
Scientists are exploring its potential to prevent cataracts, decrease the frequency of migraine headaches, augment certain types of cancer treatments and prevent preeclampsia, a common but potentially serious complication of late pregnancy.
A bit further from reality, aspirin could someday be prescribed on a short-term basis to guard against the common cold and allow vaccines to work better.
Yet, researchers are still trying to sort out the good, the bad and the ugly about aspirin.
With the exception of people at risk for heart attacks and strokes, not enough is known to recommend individuals take aspirin with their daily vitamins, says researcher Charles Hennekens of Harvard Medical School and Brigham and Women’s Hospital; he was also one of the doctors who announced last year that aspirin can cut the risk of a first heart attack by almost half.
But, Hennekens grins sheepishly, some of the new-found benefits of aspirin are so striking, it’s difficult to persuade people from taking aspirin regularly on their own.
“That’s the trouble with an over-the-counter drug,” he says.
Aspirin can cause serious side effects, which is why experts continue to advise people to consult their doctors before taking it on a regular basis.
“I do think a lot of people take aspirin on their own,” says Dr. Anthony Furlan, who has studied aspirin and stroke prevention at Case Western Reserve University in Cleveland. “But aspirin is not totally benign. It’s not a panacea.”
Aspirin helps reduce heart attacks by thinning blood to prevent the formation of clots that lodge in the heart. But the drug’s ability to thin blood can be dangerous for some people, such as those with bleeding ulcers.
Aspirin taken regularly can also cause a range of stomach problems, such as nausea, indigestion, heartburn and constipation. (Many physicians prescribe coated aspirin to minimize stomach discomfort.)
“The higher your risk, the more likely you’re willing to tolerate the side effects of the drug,” says Hennekens. “It has to be an individualized decision. There can’t be a blanket recommendation that everyone should take aspirin.”
Aspirin can be harmful to young children because of its link to a disease called Reye’s syndrome. Pregnant women are also advised to avoid aspirin.
But as researchers learn more about how aspirin works, its list of uses is likely to grow.
In the early ‘70s, scientists discovered aspirin’s healing powers stemmed from its ability to reduce the production of prostaglandins, a group of hormone-like substances released when cells are damaged.
Prostaglandins can trigger inflammation, fever and blood clotting. But aspirin destroys an enzyme, called cyclo-oxygenase, necessary for the body’s production of prostaglandins.
It is now clear, for example, that aspirin inhibits blood clotting that can trigger heart attacks and strokes, Hennekens says.
In July, 1989, the U.S. Physicians’ Health Study showed that male doctors age 50 or older who took one adult-dose aspirin every other day had a 44% lower risk of a heart attack than men taking a placebo pill.
While the study showed an overwhelming benefit, Hennekens cautions that many factors, such as a high-fat diet, sedentary lifestyle and smoking, contribute to heart disease and stroke.
“It would be unfortunate if a middle-age smoker took aspirin instead of quitting smoking,” he says. “Aspirin should be an adjunct but not an alternative for managing heart-attack risk.”
The Physicians’ Health Study also revealed that men taking aspirin had far fewer heart attacks in the morning, which, for unknown reasons, is a high heart attack risk period.
“Aspirin seemed to blunt that early-morning peak,” Hennekens says. “If this is truly the case, then it’s better to take your aspirin before you go to bed.”
Aspirin’s ability to prevent blood clots from forming also strongly appears to prevent a type of stroke caused by a clot lodging in the heart, says Dr. William Feinberg, a neurologist at the University of Arizona.
In March, Feinberg and a group of researchers announced that both aspirin and a common blood-thinning drug called warfarin decreased by 50% to 80% strokes caused by a blood clot in the heart.
“If these findings are widely applied, (taking aspirin or warfarin) could reduce strokes by 20,000 to 30,000 a year in the United States,” Feinberg says.
But beyond these discoveries, the potential wonders of aspirin are vague. Researchers are particularly uncertain about its effect in preventing heart attacks and strokes in women.
No randomized, clinical studies on aspirin and heart-attack prevention have included women, Hennekens says.
“The risks of heart attack are so much lower in women, it was important to study men first,” he says. “But we need to know whether the heart-attack risk reduction is the same in women as in men.”
And, says Furlan: “There is still the lingering question as to whether aspirin benefits women. All the physicians I know are routinely putting women on aspirin who have had a heart attack or stroke.”
But those outstanding questions concern many women, including Sydney Weisman, a Los Angeles publicist. Various physicians have suggested she take half an aspirin every other day as protection against a heart attack. Weisman, 48, has a heart condition and has a family history of heart disease.
“I took aspirin for a few months, then I heard of the possible side effects of aspirin and stopped taking it,” she says. “Most of the aspirin research has been done on men. And I don’t have a clear idea for myself of whether or not I should take it.”
Some of those questions might be answered if the National Institutes of Health decide to fund a study patterned after the Physicians’ Health Study, but this time looking at 40,000 nurses age 50 and older.
Hennekens says the proposed five-year study will also explore whether a lower dose of aspirin has the same preventive effects. Men in the Physicians’ study took a 300 milligram pill--a normal adult tablet--every other day. The women will take a 50 milligram pill, smaller than a baby aspirin, daily.
“If we can clearly show that the benefit is the same with the lower dose, it would have major impact,” Hennekens says, because a lower dose pill might cause fewer side effects.
A wealth of other ongoing studies will either enhance the reputation of aspirin or dash hopes for its emergence as a wonder drug.
* The Physicians’ Health Study has spurred interest in whether regular doses of aspirin can reduce the frequency of migraine headaches. Among doctors who have migraines, those in the study taking aspirin had 20% fewer episodes than those taking a placebo pill, reported Dr. Julie Buring at an American Heart Assn. meeting last fall.
* Researchers announced last August that small amounts of aspirin taken in late pregnancy could help reduce hypertension, which can lead to serious conditions called preeclampsia and eclampsia. Eclampsia can cause seizures in the mother and premature delivery of the baby. The studies, done in Italy and Israel, are now being repeated at several U.S. medical centers.
Aspirin is generally considered very harmful if taken during pregnancy and can cause bleeding in late pregnancy. But the studies cited found no serious side effects among the women.
“There has been a long and well-known risk for taking any drug during pregnancy. And no one is claiming that aspirin should be given during the first trimester,” Hennekens says. “We’re waiting for some more research on this, but the data we have is very encouraging.”
* Other studies are investigating whether aspirin might slow the formation of cataracts, which account for 10 million cases of decreased vision or blindness worldwide each year. Researchers speculate that aspirin lowers blood-glucose levels. High blood-glucose levels are known to predispose individuals toward cataracts. Research so far has shown two to four aspirin a day may slow the growth of cataracts by as much as several years in diabetic patients at risk.
* Aspirin might also affect the immune system by stimulating the production of interleukin-2 and gamma interferon, substances that protect the immune system, says Dr. Judith Hsia, a cardiologist at The George Washington University Medical Center in Washington.
In a study, researchers at George Washington and the University of Virginia gave a group of college students aspirin; another group received placebo pills. Both groups then had rhinovirus, which causes the common cold, sprayed directly into their noses. About 95% the students caught colds, Hsia said, but blood tests on the students who took aspirin showed increases in interleukin-2 and interferon.
“It turned out that aspirin was not effective (in preventing colds in the student sample),” Hsia says. “But it could be that getting this rhinovirus directly in your nose would produce colds in everyone.”
The researchers are now looking at whether aspirin can boost the immune system in vulnerable people, such as the elderly, diabetics and AIDS patients, so that vaccines given to those groups work better. Aspirin might also be used to strengthen the immune system for other purposes, such as to help cancer patients withstand chemotherapy better; research into this is under way at Rush-Presbyterian Hospital in Chicago.
But, Hsia says, “One problem is you can’t just take aspirin all the time for (immune system protection) because you develop a tolerance to it. One aspirin a day, every day for a week, will cause you to lose the benefit. You have to take it when you know you need the boost.”
Possible Benefits of Aspirin Preventing heart attack. Reducing tissue damage within hours of heart attack. Preventing stroke. Preventing preeclampsia in pregnancy. Preeclampsia is a condition involving high blood pressure and fluid retention. Bolstering immune system. Reducing recurrence of migraine headache.