Aspirin Therapy
Preventing Heart Attacks And Stroke

taking aspirin to prevent heart attacks


Aspirin Therapy


What Is Aspirin Therapy?
How Does It Work?
Aspirin And Heart Attacks
Preventing First Heart Events
Preventing Repeat Events
Bottom Line: Who Should Take Aspirin Therapy?
Aspirin and Diabetes
Aspirin and Cancer Prevention

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Heart Disease in Women

Other Heart Meds:

ACE Inhibitors
Beta Blockers
Calcium Channel Blockers
Water Pills
Thrombolytic Therapy

What Is Aspirin Therapy?

Aspirin (generic name acetylsalicylic acid), despite its reputation as a harmless mild painkiller, is in fact a powerful and versatile drug. As well as its ability to reduce inflammation it can also soothe pain, reduce fever and prevent blood clotting. For this reason and because it can provoke some undesirable effects, it should still be used with care. Some people are prescribed aspirin daily is a means of preventing strokes or heart attacks. Taking aspirin regularly as a preventative treatment is known as aspirin therapy. In 1948 a California doctor called Lawrence Craven first noticed that none of the 400 men he regularly prescribed aspirin to suffered heart attacks. Believing there was a link he went on to prescribe a daily therapy of an aspirin a day for all his patients. It would however take another 54 years of research before aspirin was fully accepted as a therapy for heart attack prevention. Even today, while the American Heart Association (AHA) recommends that people with stroke or heart attack risk factors talk to their doctor about a daily low-dose aspirin therapy, there still remains some uncertainty among healthcare providers as to the drug's appropriate use in different categories of patients. For example, women are far less likely to be prescribed aspirin therapy than men. This may be linked to physicians not recognizing that women are at high risk for cardiovascular (heart) disease - despite the fact that of the estimated 16.7 million people who die from heart disease every year around the globe, about 8.6 million are women. In fact deaths from stroke and heart attacks in women are responsible for twice as many female deaths than all cancers combined.

How Does It Work?

Aspirin is an antiplatelet medication which means it works by stopping platelets in the blood sticking together and forming clots. When clots occur in the arteries of the heart they can cause heart attacks, or if they occur in the arteries which supply the brain, they can cause a stroke.

Aspirin And Heart Attacks

If you think you are experiencing a heart attack (medical term, acute myocardial infarction), the AHA recommends first dialing 911 and then chewing on 1 adult aspirin tablet (unless you have any serious bleeding issues or an allergy to aspirin). Once you receive medical attention, aspirin therapy should be considered. In a large international study in the 1990s of 17,000 men and women who experienced heart attack symptoms, half were given 162 mg of aspirin within 24 hours of the onset of symptoms and treatment was continued for 30 days. The other half were given a placebo (dummy pill). The results were astounding. Within 5 weeks of treatment, the patients who received aspirin had a 23 percent risk reduction of dying from vascular complications; a 49 percent reduced risk of another heart attack and 46 percent less chance of a stroke. Yet, despite its obvious benefit, aspirin remains under-used in hospitals. One survey of more than 1,000 large American hospitals found that only 77 percent of patients with a heart attack received aspirin. In a survey of Medicare patients, only 61 percent were given aspirin within 2 days of hospitalization. It is estimated that giving aspirin to nearly all patients who suffer a heart attack would save up to 10,000 additional American lives a year.

Preventing First Heart Events: Primary Prevention

A few years ago the AHA felt there was not enough evidence to recommend the use of aspirin therapy in healthy older people as a prophylactic measure to prevent heart problems. However since data from the large-scale Women's Health Study (WHS) has become available, guidelines have now been updated. The results from the WHO study are not exactly clear-cut (which is why the treatment of certain categories of people remains debatable) but in a nutshell, it found that aspirin seems to affect women's hearts differently to men, and that age was an important factor. The survey showed that aspirin appeared to have no affect on preventing heart attacks in women, but it did help prevent stroke in women (the reverse is true for men). Confusingly however aspirin does appear to help prevent heart attacks in some older women and in those who have already had a heart attack.

Now it is recommended that doctors consider giving low-dose aspirin therapy to some women aged 65 or over, regardless of their risk factors for heart disease. Also importantly, the new guidelines now recommend an aspirin dosage of up to 325mg a day for women (and men) at high risk, as opposed to previous recommendations of 162mg a day. Additionally women of all ages, including younger women, who are at increased risk of cardiovascular events, including ischemic stroke should talk to their doctor about aspirin therapy.


Aspirin in pregnancy should always be avoided. Read also about pregnancy and heart disease.

Preventing Repeat Events: Secondary Prevention

One large scale study of 54,000 patients with a history of previous heart attacks, stroke, transient ischemic attacks (TIAs), angina attacks, atrial fibrillation, heart angioplasty, valvular disease and peripheral vascular disease found that aspirin therapy reduced subsequent recurrences by 25 percent. There were 50 fewer vascular events per 1,000 patients with unstable angina who were treated with aspirin for 6 month and 40 fewer repeat heart attacks, strokes and TIAs per 1,000 patients treated for 2 to 3 years.

Bottom Line: Who Should Take Aspirin Therapy?

Taking aspirin regularly is different from taking it occasionally for treating a headache because regular use poses some health risks. You should always discuss taking aspirin for your heart with a doctor before starting. In evaluating whether therapy is right for you, your doctor will take into account your medical history, gender, age and family history. If you have bleeding disorders, kidney disease, stomach ulcers or asthma, aspirin therapy may not be right for you. If you are recommended aspirin, it is important to follow your doctors recommended dosage, and not what is printed on the bottle label - those instructions are for general use. Do however check the label to ensure that it contains correct amount of mg recommended by your doctor.

So who should take aspirin therapy?
There are clear benefits to both men and women taking aspirin in the following circumstances:

During a Heart Attack
Chewing (not swallowing) 1 full strength or 2 baby aspirins during a heart attack can save your life.
After a Heart Attack or Stroke
After both events, taking a low dose aspirin (81 mg) every day can help prevent a second event and lessen your chance of dying of cardiovascular disease. Cardiac rehabilitation should also be considered.
High Risk Factors
If you have stable angina, diabetes, peripheral artery disease or other signs of atherosclerosis, taking a low-dose aspirin every day can help prevent heart attacks and strokes. In some cases it is also prescribed as an extra treatment for heart failure.
Experts Continue To Debate …
An aspirin a day is considered by some health experts a good idea for some healthy women over the age of 65 - that is for women who have no signs of heart disease but want to reduce their risk of stroke or heart attacks. However after the age of 79 the risk for women of internal bleeding caused by aspirin is significant. If you want to know how healthy your heart is, consider heart disease testing, including an exercise stress test.

Update 2015:
Up until now the British National Health Services (NHS) recommended patients with a common heart condition called atrial fibrillation to take aspirin. They have now taken a U-turn and no longer recommend aspirin therapy stating the risks out-weigh the benefits.

Questions To Ask Your Doctor When Considering Therapy

What are my chances of having a stroke or heart attack?
Would I benefit from taking aspirin?
Would aspirin harm me in any way?
Will it interfere with my other medications?
How long should I take it for?

Aspirin and Diabetes

People with diabetes have a 2 to 4-fold increase in risk of dying from cardiovascular disease complications. Both women and men are at increased risk. Aspirin therapy is recommended in the following instances:

A daily dose of 75–162 mg a day in diabetic women and men with a history of heart attacks, coronary bypass surgery, stroke, peripheral vascular disease and/or angina.

A daily dose of 75–162 mg a day in women and men with types 1 and 2 diabetes with high heart disease risk factors.

Those with aspirin allergy and recent gastrointestinal bleeding are not candidates but other antiplatelets may be an alternative for patients at high risk.


The WHS study found that following coronary heart disease prevention advice such as exercising regularly, maintaining a healthy body weight and not smoking can reduce a woman's risk factors by up to 84 percent. Yet of the 40,000 women surveyed, only 3 percent practiced those guidelines. So, the alternative to taking aspirin as a way to prevent first heart attacks and strokes is to practice clean living.

Aspirin And Cancer Prevention

According to a study by the Harvard Medical School, breast cancer patients who take aspirin may reduce their risk of dying from breast cancer by 71 percent. The study surveyed 4,000 registered nurses between 1976 and 2006 who took aspirin regularly (2 to 5 days a week). Researchers are not sure why this should be, but theorize it may be because aspirin helps to control cancer by fighting inflammation. Breast cancer cells produce more inflammatory materials than regular breast cells, and aspirin appears to prevent the cancer cells from growing and spreading. The study found the aspirin may also help fight colon cancer. Scientists say more research into breast cancer prevention is necessary and aspirin therapy needs to be used with caution - it may pose problems for women undergoing cancer treatments such as chemotherapy because it can cause gastric bleeding.

  Related Articles on Aspirin Therapy

For more information, see the following:

Coronary Heart Disease in Women
Living With Heart Disease

Back To Homepage: Womens Health Advice

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