Aspirin is one of our oldest medications. The Bayer company first began marketing aspirin in 1899. But Chinese healers were using willow bark, the precursor to modern-day aspirin, as far back as 500 B.C. It is surprising, then, that there is still so much controversy over aspirin 120 years after it became available. Doctors debate whether patients should take aspirin or avoid the “wonder” drug.
Aspirin for the Heart? A Very Slow Start!
It all began with a chance observation by a general practitioner in Glendale, California. Shortly after the introduction of aspirin-containing chewing gum (Aspergum), Dr. Lawrence Craven began handing out packages of this chewing gum to patients who had undergone tonsillectomies.
He instructed them to chew one stick of gum (containing 226.5 mg or 3.5 grains of aspirin):
“one half hour before each meal and at bedtime in order to enable them to eat and sleep well.”
(Annals of Western Medicine, Feb. 1950)
Dr. Craven’s regimen (just under three regular-strength tablets per day) did appear to provide some pain relief, but an unexpected problem occurred:
“… several of my patients had serious postoperative hemorrhages which were difficult to control. The bleeding was sometimes so severe that hospitalization was necessary. In each instance the laboratory reported a prolonged coagulation time.”
A Chance Discovery and an Explanation:
After checking with these patients, Dr. Craven found that they had been so pleased with the Aspergum that they had purchased additional packets and were consuming extra sticks daily. It could have ended there, but Dr. Craven reviewed the medical literature of the time and discovered that salicylates had a powerful anticoagulant effect.
He went on to speculate that
“…if further study confirms the impression that acetylsalicylic acid [aspirin] prolongs coagulation time, it would appear that the drug might be of value as a preventative of vascular thrombotic conditions, including coronary thrombosis [heart attack].”
Dr. Craven soon put this theory into practice. In 1950 he reported that:
“…during the past two years, I have advised all of my male patients between the ages of 40 and 65 to take 10 to 30 grains [two to six regular–strength tablets] of aspirin daily as a possible preventive of coronary thrombosis. More than 400 have done so, and of these, none has suffered a coronary thrombosis.”
Encouraging Patients to Take Aspirin:
Over the next six years Dr. Craven continued his research with smaller aspirin doses, encouraging friends and patients to take one tablet daily. He reported that this regimen could prevent heart attacks in otherwise healthy men or could prevent recurrences in those who had already suffered a coronary thrombosis.
Dr. Craven reported that:
“…approximately 8,000 men have adopted the regime calling for from 5 to 10 grains [one to two tablets] of aspirin daily, with a surprising result. Not a single case of detectable coronary or cerebral thrombosis [clotting stroke] has occurred among patients who faithfully have adhered to this regime.”
(Mississippi Valley Medical Journal, Sept. 1956)
Ignored and Forgotten:
Dr. Lawrence Craven’s observations were almost completely ignored by the medical establishment. It wasn’t until the 1970s that large–scale aspirin studies began reappearing. In 1989, the American College of Chest Physicians recommended that people at risk of coronary artery disease should take aspirin daily (one regular-strength tablet).
Should Healthy People Take Aspirin?
For decades, doctors recommended low-dose daily aspirin to prevent heart attacks and strokes in otherwise healthy people. That was largely because of the Physicians’ Health Study published in the New England Journal of Medicine (July 20, 1989).
In this randomized controlled trial, healthy male physicians took regular aspirin or placebo every other day. After five years, the aspirin takers had experienced 44 percent fewer heart attacks.
A study published two years later (Annals of Internal Medicine, May 15,1991) on a subgroup of men with chest pain (stable angina) concluded that the risk of a heart attack was 87 percent lower if they took aspirin every other day. Such data eventually convinced a lot of doctors to prescribe aspirin to prevent heart attacks in healthy people.
The Dark Side of Aspirin:
Remember that Dr. Lawrence Craven started studying aspirin because it caused bleeding in patients who chewed too much Aspergum after surgery. Since then, we have learned that people who take aspirin regularly can indeed suffer dangerous hemorrhages. Recent research has suggested that nearly as many healthy people experience harm as are protected from heart attacks when they take aspirin.
That has led the American Heart Association to recommend that aspirin be reserved for people at high risk of heart attacks or clotting strokes. New reports about aspirin studies have scared a lot of people. For example, one headline read:
“Taking a daily aspirin causes the risk of major bleeding to increase by 43 per cent, study claims.”
That sounds terrifying. However, the actual rate of major bleeds was 2.3 in 1,000 people taking aspirin and 1.6 in 1,000 people not taking aspirin. That means an extra five people per 10,000 would have a major bleed if they take aspirin (JAMA, Jan. 23, 2019). That is worrisome, but it sounds a lot less foreboding than 43%.
Heart attack prevention is not the only potential benefit of aspirin, however. Researchers have been looking at its anticancer activity for decades.
Should People Take Aspirin Against Cancer?
The most recent research was published in JAMA Network Open (Dec. 2, 2019). Investigators tracked 146,152 individuals for an average of 12.5 years. These were individuals who had been diagnosed with colorectal, lung, prostate or ovarian cancer.
People who took aspirin three or more times a week were less likely to die during the study from cancer in general and colorectal cancer in particular. All-cause mortality was also lower among aspirin takers.
The article concludes:
“In this cohort study, we found a significant association of aspirin use with reduced all-cause, any cancer, GI cancer, and CRC [colorectal cancer] mortality among individuals 65 years and older in the PLCO [Prostate, Lung, Colorectal, and Ovarian] Cancer Screening Trial.”
The Pros and Cons of Aspirin:
Like all drugs, aspirin has both benefits and risks. Because it is old and only costs pennies a dose, it may not get the respect it deserves.
However, there are relatively few drugs that have been proven to prevent cancer or prolong life after metastases, especially at such a low price. After more than 120 years, perhaps we should reconsider the value of aspirin and resurrect the old Bayer aspirin tagline:
“The wonder drug that works wonders.”
No one should ever take aspirin on a regular basis without first checking with a physician. Some people are at such a high risk of bleeding that aspirin is absolutely inappropriate.
If you take aspirin, you should always be monitored regularly by a physician. Many medications can interact with aspirin. That would be another reason you should not take aspirin if you are on a medicine that is incompatible with ASA. A pharmacist can check for drug interactions.
Learn more about aspirin as an anticoagulant at this link:
Deciding whether the benefits outweigh the risks is complicated. Here is an article that will help you and your doctor make that decision:
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