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Wonder Drug Aspirin does it all. It has long been known to offer significant protection against heart attack and stroke. More recently, it has been shown that aspirin's anti-inflammatory effect not only helps with killing pain but also decreases the risk of colon and breast cancer, and it may also slow the development of Alzheimer's disease. With the safety and effectiveness of COX-2 inhibitors such as Vioxx, Celebrex and Bextra recently called into question, aspirin is again ascendant. Here's everything you need to know about this little pill and who should and shouldn't take it:
Aspirin, ibuprofen and naproxen belong to a class of drugs known as nonsteroidal anti-inflammatories, all of which inhibit the enzymes (cyclooxygenase 1 and 2) that make prostaglandins. (Prostaglandins are chemicals that cause the uterus to contract, mediate inflammation and help maintain the protective coating of mucus in the stomach.) This is why blocking prostaglandins, as aspirin does, can alleviate pain and inflammation, but can also cause ulcers.
Aspirin was first manufactured in 1897, and, within two years, became the most widely used medication in history. It's now found in more of the world's medicine cabinets than any other pill. It was even included as reparations in the Treaty of Versailles at the close of World War I. The ancient Greeks used the bark of the willow tree to relieve pain and combat fever without knowing what it contained. Maimonides also wrote of these effects in the 12th century. It wasn't until the 19th century, however, that Johann Buchner, a German chemist, isolated an active glucoside from the bark, calling it salicin (after Salix, the Latin name for the willow tree). Sodium salicylate then became a useful medication to treat pain, particularly joint aches, despite the medicine's bitter taste and tendency to irritate the stomach. In 1897, Felix Hoffman, an employee of a German fabric-dyeing company known as Bayer, sought a chemical to lessen the misery of his father's arthritis. He came upon acetyl salicylic acid (ASA), produced by the company's chemists but then ignored. ASA proved to be quite effective for his father's pain, and it lacked the bitter taste and some of the stomach upset of sodium salicylate. Bayer patented ASA and called it Aspirin. The Aspirin tablet, as a substitute for powder, was introduced in 1900. It was prescription only and was used for headaches, colds, menstrual cramps and inflamed nerves, much as it is today. Aspirin became available over the counter in the United States in 1915, although its price for Americans remained 10 times what Germans were paying. The Bayer company tried to extend its patent rights beyond their 1917 expiration date, but World War I thwarted this effort. The U.S. Justice Department assumed total control of Bayer's U.S. property as enemy-owned. Aspirin was then produced as an American product.
With the explosion in the number of nonsteroidal anti-inflammatory drugs available on the market, both over the counter and by prescription, aspirin as a simple painkiller or anti-inflammatory treatment has been obscured. But aspirin is very effective at treating common headaches, joint aches, backache and many kinds of arthritis. And aspirin is far cheaper than many of the latest painkillers. Since aspirin is shorter-acting than most of the currently used NSAIDs and related specific Cox 2 inhibitors (cyclooxygenase 2), it has the advantage of "wearing off." If you experience a side effect with one of the longer-acting drugs, it may take a full day before the side effect eases.
Aspirin's effectiveness at preventing heart attacks has been tied to its anti-platelet effects, the sticky blood components that initiate clots. Low-dose aspirin inhibits cyclooxygenase, the enzyme that makes platelets sticky. Since over 90% of heart attacks are caused by a clot breaking loose and occluding an already narrowed artery, aspirin has been shown to markedly decrease the chances of that culprit clot forming. Many doctors recommend that patients at some risk of a heart attack, including most men over 40 and women after menopause, take a baby aspirin (81 mg) every day. These patients should speak to their doctor about which painkillers are safest to take with aspirin, as drug interactions must be considered. Despite some controversy, it appears that monitored doses of Tylenol, ibuprofen and other NSAIDs can be safely taken with aspirin, though the risk of side effects can be cumulative. Though some recent studies have questioned the effects of aspirin at preventing heart attacks, the vast body of medical research supports the contention.
Aspirin is a well-known preventive against strokes, utilizing its effects as an anti-platelet drug that prevents the early formation of blood clots in the brain. All blood clots initiate with the adherence of platelets to the walls of blood vessels. Aspirin prevents this from happening. Recently, aspirin has been shown to be effective at decreasing inflammation-mediated disease in the brain. A study of 3,000 patients in Utah in 2002 revealed a 45% reduction in the incidence of Alzheimer's disease in patients who were taking aspirin at least four times a week. The exact mechanism of action is not known, though it's believed that the anti-inflammatory effects of aspirin may lead to a reduction of amyloid plaques, characteristic of Alzheimer's disease.
One of the primary ways that aspirin stops inflammation is to block prostaglandin production. And prostaglandins are intimately involved in the production of the female hormone estrogen. It is therefore a popular theory that prolonged aspirin use may cut down on the incidence of estrogen-dependent tumors. A study in the May 2004 Journal of the American Medical Association looking back on more than 1,400 patients with breast cancer and 1,400 without the disease found that women taking daily aspirin had a 26% lower risk of developing estrogen-stimulated tumors, the most common type of breast cancer. More than 200,000 women develop breast cancer each year. Since over half of the new cases are estrogen-sensitive, aspirin use could help to prevent more than 30,000 cases! These findings add to a growing body of evidence that aspirin, by blocking certain prostaglandin synthesis, can decrease production of estrogen that can lead to breast cancer. The authors of the aspirin/breast cancer study are cautious. They conclude, "Since this is the first study, to our knowledge, that examined whether the protective effect of aspirin may be limited to hormone receptor-positive breast cancer, our findings need to be replicated before drawing definitive conclusions." Consulting a physician can help you determine if you're in an ever widening group of patients who should be taking aspirin prophylactically. Women with a higher than normal risk of breast cancer should be considered for aspirin therapy right now. A woman's family history should be factored into the equation. Not everyone should take aspirin to prevent breast cancer. A cost-benefit analysis must be done in each case before telling a patient to take aspirin for this reason. But aspirin as a preventive against breast cancer looks very promising.
Aspirin's role as an anti-inflammatory agent also appears to interfere with the growth of intestinal cancer cells and their ability to attract a blood supply. It appears that the anti-inflammatory effect also slows the rate of mutation from normal cells to atypical cells and further degradation into tumor cells. Colon cancer is the second-leading cancer killer in the U.S., responsible for 48,000 deaths annually. Large population reviews have shown that regular aspirin users have only about half as much colon cancer as nonusers. In 2002, a study at Dartmouth Medical School was the first to show a link between taking aspirin and reducing the number of polyps that lead to cancer. The study looked at 1,121 people who had colon polyps removed. During repeat screening three years later, the researchers found that only 38% of those getting baby aspirin had new polyps, compared with 47% of people getting placebos. This month, a study at the Dana-Farber Cancer Institute in Boston showed that of 850 people who underwent surgery for colon cancer, those who took aspirin regularly were half as likely to die or have their cancer return.
The chemical compound in aspirin, acetylsalicylic acid, is related to the salicylates found in fruit and vegetables (and highly concentrated in tree bark, especially willow). Berries are a good source. Herbs, spices and tea also contain high amounts. In Europe, there is a plant called spirae, which grows in wet areas and contains high amounts of an aspirin-like salicylate. It can be taken as an herb with similar effect. Of course, it is these salicylates that are believed to have the protective effect against colon cancer and heart disease that aspirin is credited with. Since the average American diet is generally low in fruit and vegetables and therefore low in salicylates, this could help explain the increased incidence of these diseases, as well as the preventive effect of aspirin taken as a supplement.
But not everyone should take aspirin, because the drug is not free of side effects. Since aspirin causes platelets to become less sticky, the risk of bleeding is increased at least twofold. The primary organs at risk for aspirin-related bleeding are the stomach and the brain. Gastric irritation and bleeding are common side effects. Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) are responsible for 16,500 deaths annually and more than 100,000 hospitalizations in the United States as a result of peptic ulcers and gastrointestinal complications. People who already have had ulcers or gastrointestinal bleeding should be carefully screened before considering aspirin. Heavy drinkers must also watch out because alcohol compounds the effect of aspirin to irritate the stomach lining. Anyone experiencing heartburn, queasiness, or blood in their stool should consult a physician before taking aspirin. Physicians should check every aspirin user for occult blood in the stool at least once yearly. Hemorrhagic stroke occurs in about 1 in 1,000 people on aspirin. Heavy alcohol users, people with bleeding disorders, those at risk for falls, and those with prior strokes are at greater risk for a bleed in the brain. Aspirin allergy is fairly rare, but aspirin is often poorly tolerated by patients with asthma or kidney disease. Aspirin can also cause sodium retention, raising blood pressure. The risk of all these side effects is greatest for people who take daily doses for arthritis or other common problems. A recent study in the Archives of Internal Medicine revealed that many patients told to take 81 mg of aspirin by their doctors to help prevent heart attack and stroke were actually taking 325 mg or more, which increased their risk of bleeding. Those over 65 are also more susceptible to drug side effects because of slowing metabolism and frailer organs.
Aspirin, like all products, can be beneficial, or can be misused or abused. But in weighing the pros and cons of aspirin, it remains a great drug, with a multitude of uses, appropriate for most of the population. Clearly, if you have gastric ills or heartburn, you should be supercareful, and rely on the guidance of your physician. But if you’re in good health and do not have major risk factors for bleeding, you can consider aspirin to protect you from many diseases or to ease your pain. |
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Copyright © 1990-2007 Marc K. Siegel, M.D. |
