Aspirin first appeared in the spring of 1899 in a handful of articles in a few German medical journals. The authors introduced it without fanfare as a serviceable substitute for the salicylic acid and sodium salicylate that had been in use for more than twenty years to treat rheumatic disorders. Aspirin has been used for over 100 years, but its beneficial effects to prevent stroke and heart attack only started to be recognized in the 1970s.
Aspirin, which is also called acetylsalicylic acid, is the drug that is most widely used as an analgesic, or pain reliever; antipyretic, or fever reducer; and anti-inflammatory agent. Its activity is based on chemicals called salicylates. It occurs as white crystals that are commonly tabular or needle-like, or as a white crystalline powder. It has become the standard by which all other analgesics and antipyretics are measured.
Aspirin is most effective in relieving slight to moderately severe pain, particularly headache, muscle aches, and joint pains. Its effects are said to be less effective against deep-seated pain originating in internal organs. Because it suppresses inflammatory processes while relieving pain, it is still the treatment of choice for arthritis and related disorders. Aspirin reduces fever by increasing blood flow to the surface, thereby promoting sweating and heat loss from the body.
Aspirin has been used as a nonprescription pain reliever for more than 100 years. However, it was not until the 1970s that the mechanism of action was discovered; aspirin was found to inhibit the production of pro-inflammatory prostaglandins (Phelps, 2004).
The increasing interest of the public and the health communities in aspirin has come about largely because of fairly recent advances in understanding how it works. What is it about this drug that, at small doses, interferes with blood clotting, at somewhat higher doses reduces fever and eases minor aches and pains, and at comparatively large doses combats pain and inflammation in rheumatoid arthritis and several other related diseases.
There is evidence that all the therapeutic effects of aspirin involve the inhibition of the synthesis prostaglandins, fatty acids with hormone-like functions. This effect has been linked to the prophylactic use of aspirin, specifically the prevention of blood clots in potential stroke and heart-attack victims. A number of studies have conclusively shown that aspirin can significantly reduce the risk of heart attacks, strokes and other serious disorders of the vascular (blood) system. Therefore aspirin is effective not only against everyday ailments, but is also useful as a preventative treatment for heart attacks, strokes, and even some types of cancers.
Aspirin, used in the past for headaches, fevers and aching joints, is now widely used in the fight against cardiovascular disease and looks like a good bet to ward off colon, prostate and pancreatic cancer and perhaps cancers of the esophagus, stomach and rectum, as well. Evidence gathered suggests that all people over the age of 20 years could benefit from taking a low dose of aspirin per day. Various researches can attest to this.
Aspirin is an effective antiplatelet drug. It irreversibly acetylates and thus inhibits the platelet cyclooxygenase system involved in formation of thromboxane A2, a potent aggregator of platelets and also a vasoconstrictor. Aspirin also inhibits production of prostacyclin by endothelial cells. Indications for treatment with aspirin thus include the management of angina and evolving myocardial infarction and also prevention of stroke and death in patients with transient cerebral ischemic attacks (Murray, et al, 2000). Aspirin produced for this purpose often comes in 75 or 81 mg dispersible tablets and is sometimes called “Junior aspirin.” High doses of aspirin are also given immediately after an acute heart attack. These doses may also inhibit the synthesis of prothrombin and may therefore produce a second and different anticoagulant effect.
Once aspirin’s benefits for patients with cardiovascular disease were established, scientists sought to learn whether regular aspirin use would prevent a first heart attack in healthy individuals. The findings regarding that critical question have thus far been equivocal.
Aspirin’s role in preventing initial cardiovascular events in women was dramatically focused by the results of the first study to test aspirin prophylaxis in a large number of apparently healthy women (Zoler, 2005).
In one study, the results showed that among women at least 65 years old, a regimen of 100 mg of aspirin every other day cuts the incidence of ischemic stroke, myocardial infarction (MI), and all major cardiovascular disease (CVD) events, while causing a small number of adverse events. Among women younger than 65, the benefit was limited to cutting the risk of ischemic strokes, and the reduction was so modest that aspirin prophylaxis will have to be targeted to a select group of women for whom the likely benefits of regular aspirin will outweigh the risks (Zoler, 2005). Prophylactic aspirin therefore is an option for women aged 65 or older if their blood pressure is controlled.
Men and women who have diabetes have a much higher risk of dying from heart and blood vessel disease than other people do. Many studies (including some with people who have diabetes) have found that low-dose aspirin lowers the risk of a second stroke or heart attack. It also lowers the risk of heart attack in people who have angina. Studies suggest that aspirin can also prevent heart disease from developing in people who are at high risk. So aspirin is a simple and cheap way of lowering risk of heart disease (Roberts, 2003)
For prevention of transient ischemic attacks, 1-1.3g daily in 2-4 divided doses of aspirin is recommended. Doses as low as 325 mg per day may be used in individuals who are tolerant of the higher dose. In prevention of MI, 300-325 mg per day is recommended but doses as low as 80 mg per day may be effective.
Another study found that taking aspirin every day for five years lowers the chances of developing cancers of the mouth, throat and esophagus by two thirds. Another study shows that a daily dose cuts by a third the risk of colon polyps – small growths considered to be precursors to colorectal cancer (Connor, 2003). These findings come on top of well-established evidence over the past 20 years showing that aspirin can significantly reduce the probability of a heart attack or stroke.
Regular aspirin use was inversely associated with hormone-responsive breast tumors, with the strongest results for women who took 7 or more tablets per week. This study adds to the growing body of data that supports the regular use of aspirin as an effective chemopreventive agent for hormone-responsive breast cancer tumors. This effect most likely occurs through the inhibition of prostaglandin and subsequent inhibition of estrogen biosynthesis. However, the reduced risk must be confirmed before clinicians can make definite recommendations to women at risk for breast cancer (Phelps, 2004).
Nonsteroidal anti-inflammatory drugs (NSAID) drugs, which can believe pain and reduce inflammation, often are the only therapy needed for patients who are able to move their joints with relative ease. Oldest of the NSAIDs is plain aspirin, still the most frequently prescribed arthritis drug. Aspirin, however, has its drawbacks. The large doses required for effective treatment–as many as 18 to 20 tablets a day–may cause stomach irritation and gastrointestinal bleeding. Ringing in the ears, temporary hearing loss, and interference with blood clotting are also common side effects. Some of aspirin’s side effects can be reduced by using buffered or timed-release versions .
Low-dose aspirin therapy is used routinely for the prevention of arterial thrombosis. Elderly patients tend to have adverse reactions to aspirin, including renal effects. In high dosages, aspirin tends to increase uric acid excretion, while lower dosages may cause its retention. Aspirin therapy at the anti-inflammatory dosage level has been shown to have a negative effect on renal function in patients with renal insufficiency, cirrhosis, or heart disease (Miller, 2004). The authors conclude that short-term, low-dose aspirin therapy may have a significant adverse effect on renal function in elderly patients. They note that this negative effect persisted for at least three weeks after aspirin therapy was discontinued.
Add to all that its beneficiary role in a host of other conditions from Alzheimer’s to gum disease, and you have a medicine of unparalleled importance to humankind. The story of aspirin is one rich in dramatic twists and surprising discoveries (Jeffreys, 2005). Additional studies have suggested that it might even improve memory (Smith, 2004).
Aspirin is considered a relatively safe drug. But despite the overwhelming evidence of aspirin’s benefits, it can have side effects. One study found that men with high blood pressure are unlikely to benefit from aspirin’s anti-stroke effects, and might even put themselves at higher risk if they take the drug each day. A number of studies have also shown that the drug can produce gastro- intestinal bleeding. Oxford researchers who analysed 24 studies found that bleeding occurred in 2.5 per cent of patients taking aspirin, compared with 1.4 per cent in those who did not (Connor, 2003).
Aspirin’s chief drawback is its ability to irritate the lining of the stomach and cause bleeding. In very large doses, aspirin is toxic and can cause kidney damage. In sever cases, it may even cause death. Aspirin, even in low doses, is associated with many adverse events, primarily of gastrointestinal tract bleeding. These risks appear to be unrelated to the risks of CVD. So there is considerable variation in the overall risk-benefit ratio for an individual as those with low CVD risk will be at the same risk level of gastrointestinal bleeding as those at high CVD risk (Gadsby, 2005).
Aspirin can irritate the stomach lining and cause heartburn, pain, nausea, vomiting, and, over time, more serious consequences such as internal bleeding, ulcers, and holes in the stomach or intestines. Chronic alcohol users may be at increased risk of stomach bleeding, as well as liver damage, from aspirin use (Nordenberg, 1999).
Aspirin may increase the risk of bleeding with warfarin, heparin, heparin-like agents, thrombolytic agents, ticlopidine, clopidegrel, tirofiban, or eptifibatide, although these agents are frequently used safely in combination and in sequence.
At high doses, aspirin may cause temporary ringing in the ears and hearing loss, which usually disappear when the dose is lowered. Facial swelling and sometimes an asthma attack may occur in the two out of 1,000 people who are allergic to aspirin (Nordenberg, 1999).
Another serious and potentially fatal side effect of aspirin is brain hemorrhage or bleeding. Aspirin is a blood thinner and interferes with the normal clotting mechanisms of the body. Because of this property, it can cause bleeding and bruises. Aspirin’s antiplatelet activity apparently accounts for hemorrhagic strokes, caused by bleeding into the brain, in a small but significant percentage of persons who use the drug regularly.
For the great majority of occasional aspirin users, internal bleeding is not a problem. But aspirin may be unsuitable for people with uncontrolled high blood pressure, liver or kidney disease, peptic ulcer, or other conditions that might increase the risk of cerebral hemorrhage or other internal bleeding.
To summarize, there are many established health benefits of aspirin. Aside from preventing heart attacks and strokes, lately, there have been studies showing that aspirin may also prevent some cancers of the colon. Metaanalysis of aspirin data provided the following conclusions: (1) aspirin is clearly beneficial for individuals who had a heart attack or stroke, (2) aspirin is also beneficial for individuals who have diabetes and high cholesterol levels. But it is important to note that aspirin alone does not altogether rid the individual of the diseases. Healthy habits are also very important.
Aspirin can help prevent a heart attack or clot-related stroke by lowering the clotting action of the blood’s platelets. But the same properties that make aspirin work in stopping blood from clotting may also cause unwanted side effects, such as stomach bleeding, bleeding in the brain, kidney failure, and other kinds of strokes. There may be a benefit to daily aspirin use if an individual have some kind of heart or blood vessel disease, or if he or she has evidence of poor blood flow to the brain. But only a doctor can tell if whether the risks of long-term aspirin use may be greater than the benefits for an individual.
Better understanding of aspirin’s myriad effects in the body has led to clinical trials and other studies to assess a variety of possible uses: preventing the severity of migraine headaches, improving circulation to the gums thereby arresting periodontal disease, preventing certain types of cataracts, lowering the risk of recurrence of colorectal cancer, and controlling the dangerously high blood pressure (called preeclampsia) that occurs in 5 to 15 percent of pregnancies.
Aspirin is affordable. It does not require a prescription. And many people are taking it. Although aspirin is a familiar and readily available drug, people shouldn’t take it for its cardiovascular and other benefits without discussing the risks of long-term use with a doctor. Therefore, before anyone would undergo daily aspirin therapy, the first most important thing to do is to consult a doctor. Although aspirin could have beneficial effects, it may vary from one individual to another.
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