Kristi M. Isaac, BS, PharmD

Dr. Williams is a PGY-1 pharmacy resident and Dr. Isaac is a clinical assistant professor of pharmacy at Xavier University of Louisiana College of Pharmacy in New Orleans.

Aspirin is one of the most widely used OTC drugs. Its anti-inflammatory and antipyretic effects make it beneficial for use in the treatment of mild-to-moderate pain and fever. The antiplatelet effects of low-dose aspirin also make it effective for the pri-mary and secondary prevention of cardiovascular disease and stroke. Aspirin supplementation also has been linked with beneficial effects in various cancers and Alzheimer’s disease.1

Considering the number of established and emerging uses of aspirin, patients may have questions concerning the beneficial ef-fects of its use. It is important that pharmacists are aware of the many uses of aspirin and are able to provide appropriate informa-tion about the benefits and risks.

Primary Prevention of Cardiovascular Disease and Stroke

An estimated 36% of US adults take aspirin regularly for cardiovascular disease and stroke prevention.2 The US Preventive Ser-vices Task Force (USPSTF) published a recent update to their recommendations for the use of aspirin for the primary prevention of cardiovascular disease. The USPSTF recommends the use of low-dose aspirin in men aged 45 to 79 and women aged 55 to 79 when the benefit of a reduction in myocardial infarction in men or ischemic stroke in women outweighs the risk of gastrointestinal (GI) bleeding.3

The USPSTF provides recommendations for aspirin use according to sex due to evidence suggesting that aspirin may have dif-ferential effects in men and women. Evidence suggests the benefits of aspirin use for primary prevention are derived from a reduc-tion in myocardial infarction in men and a reduction in ischemic stroke in women.3-5 Consequently, before making a recommenda-tion to initiate low-dose aspirin in individuals without a history of coronary heart disease (CHD) or stroke, it is important to assess CHD risk in men and stroke risk in women.

The USPSTF provides links to online tools to assess CHD and stroke risk. There is a CHD risk calculator available at http://hp2010.nhlbihin.net/atpiii/calculator.asp?usertype=prof, and a stroke risk calculator available at www.westernstroke.org. The CHD and stroke risk should be weighed against the risk for bleeding. Risk factors for GI bleeding include increasing age, male sex, upper GI tract pain, GI ulcers, concomitant nonsteroidal anti-inflammatory drug (NSAID) use, uncontrolled hypertension, and con-comitant use of anticoagulants.2

Table 1 provides the 10-year CHD and stroke risk levels at which the number of these events prevented by aspirin is closely balanced to the number of serious bleeding events.

This table, along with the risk calculators, can be useful when deciding whether to recommend daily low-dose aspirin therapy in an individual patient.

As the 10-year risk of CHD or stroke increases above the values listed in the table, the recommendation to take aspirin should become stronger.3 Daily low-dose aspirin is not recommended for the primary prevention of stroke in women younger than 55 years or for the prevention of myocardial infarction in men younger than 45 years of age.

The appropriate long-term daily dose of aspirin remains controversial. In clinical trials, however, doses of 75 to 81 mg/day were as effective as higher doses for cardiovascular disease prevention.2,6 Doses exceeding 81 mg are associated with an increased risk of bleeding.2,6

Among the possible emerging uses of aspirin include the prevention of cancer and the treatment of Alzheimer’s disease.1 One trial examining the effectiveness of aspirin as a chemoprotective agent against colorectal adenomas revealed a 19% relative reduction in the risk of recurrent colorectal adenomas in patients with a history of the tumors who were randomized to receive aspirin 81 mg daily.7

The Baltimore Longitudinal Study of Aging demonstrated that aspirin might be of benefit for Alzheimer’s disease patients. Among patients with 2 or more years of aspirin use, the relative risk of Alzheimer’s disease was 0.4 (95% confidence interval, 0.2-0.8).8 The authors concluded that aspirin may reduce the inflammatory process in Alzheimer’s disease. Further research is neces-sary before recommendations can be made concerning benefits of aspirin in the prevention of cancer and the treatment of Alz-heimer’s disease.

Bleeding events, including GI bleeding and hemorrhagic stroke, are the most serious adverse effects associated with daily aspirin therapy. Low-dose aspirin carries a small, but significant risk of upper GI bleeding.9 Risk factors for GI bleeding include advanced age, male sex, a history of GI ulcers, and concomitant NSAID use.3 

Although small, there is a risk of hemorrhagic stroke associated with the use of low-dose aspirin for the primary prevention of CHD or stroke, with an estimated 0.2 events per 1000 patient-years.10 Risk factors for hemorrhagic stroke with chronic aspirin use include a history of intracranial hemorrhage, advanced age, and uncontrolled hypertension.10

The presence of any of the risk factors mentioned is not a contraindication for daily aspirin use. In some patients the benefits of therapy may outweigh the risk of bleeding. All patients should be informed of the risks associated with daily aspirin therapy.

Several drug interactions are associated with aspirin. Aspirin may increase methotrexate serum levels and may displace valproic acid from its binding site, which can result in toxicity.11,12 Concomitant use of oral anticoagulants, low-molecular-weight heparins, NSAIDs, and other antiplatelet agents can increase the risk of bleeding and GI ulceration.12

When given with ibuprofen, the potential exists for the attenuation of the antiplatelet effects of aspirin.13 Patients should be advised to take aspirin 8 hours before, or 30 minutes after, ibuprofen ingestion to avoid this potential interaction. Additionally, the effects of angiotensin-converting enzyme inhibitors may be blunted by aspirin administration, but this effect may only be significant at higher doses of aspirin.12

Patients also should be notified of herbal supplements that have antiplatelet activity, including cat’s claw, dong quai, feverfew, garlic, ginger, ginkgo- biloba, green tea, and ginseng.14

After assessing CHD and stroke risk along with risk factors for bleeding, pharmacists can assist patients in determining whether daily low-dose aspirin may be appropriate. Patients should, however, consult their physician before beginning daily aspirin therapy. Table 2 provides tips for counseling patients regarding daily low-dose aspirin therapy. Pharmacists also can provide information on the benefits as well as the risks associated with the use of daily OTC aspirin.

Articles

The Many Uses of Aspirin

Smoke that is produced by cigars  or cigarettes is known as secondary  smoke or environmental  tobacco smoke (ETS). This smoke contains  chemicals that are harmful to the  human body, such as hydrogen cyanide,  benzene, and formaldehyde. These products  are carcinogenic and toxic, causing  increased risk for lung cancer, asthma,  respiratory infections, and some  types of heart disease. Secondary  smoke exposure has been noted to  worsen asthma symptoms in 400,000  to 1 million asthmatic children.

Approximately 35% of children in  America live with caregivers who  smoke or have visitors who smoke in  the home regularly.

It is necessary to  educate parents about the dangers of  secondary smoke on asthmatic children.  Members of the health care community  can play a pivotal role in providing  this information.

When tobacco smoke is inhaled,  physiologic changes occur in the lungs.  The cilia, tiny hairs in the lungs, are a  natural defense against foreign objects  entering deep into the bronchial tree.  These cilia push particles upward,  moving them out of the lungs, and then  they often are swallowed. When the  toxins in secondary smoke are introduced  into the lungs, cilia function  decreases, along with the number of  cilia produced. The cleaning process is  hindered, leaving the lungs more susceptible  to infection.

Mucus production is increased with  exposure to cigarette smoke because  of the increased number of mucus  cells and their cell size. Excessive  mucus trapped in the lungs causes  infection, cough, and narrowed airways.

The carcinogenic chemicals in secondary  smoke cause the cells in the  lungs to change composition, making  cancer occurrence more likely. Some  common effects due to ETS are cough,  shortness of breath, wheezing, lung  infections, and increased symptoms of  asthma.

Retrospective studies have analyzed  the effects of secondary smoke in children.  To find a correlation between  secondary smoke and asthma exacerbations,  one study analyzed 954 children  who presented to the emergency  department with acute asthma. Approximately  36% of the caregivers  reported that their child was exposed  to ETS. Of this subgroup, 65% were  exposed daily. Asthmatic children exposed  to ETS were significantly more  likely to be girls, to come from a lower-income  family, to have pets at home,  and to use their controller medications  less. There was a weak association  between the severity of the asthma attack  and the exposure to secondary  smoke.

Other studies have been conducted  to determine the effects of smoking  bans and education on the caregivers  of asthmatic children. 

are defined as prohibitions on smoking  in certain environments, such as  homes, vehicles, restaurants, or workplaces.

One study found that children  living with smokers were 10 times less  likely to have smoking bans in place.  Most health care professionals (82%)  counseled patients about smoking  bans in the home environment, but  60% forgot to ask about smoking in a  vehicle. The study concluded that a significant  portion of asthmatic children  are not being protected by smoking  bans in their own homes, and so it is  necessary to educate parents about  smoking bans and cessation.

In another study, parents of asthmatic  children were educated twice a week about secondary smoke and  were instructed to limit the amount of  ETS exposure to their child. The result  was a 40% to 80% reduction of exposure  to ETS, when compared with  baseline exposure. The study also  showed during later follow-ups that  parents continued these precautions.

It is imperative to try to decrease the  amount of ETS to which asthmatic children  are exposed. The American Lung  Association recommends that cigarette  smoke should be avoided in the  homes of asthma patients, especially  children. Children's asthma condition  has been shown to improve when the  parents decline from smoking in their  environment.

As pharmacists, it may seem difficult  to talk to parents or caregivers about  this issue. The Table provides helpful  tips for pharmacists on counseling parents  on secondary smoke in order to  benefit asthmatic children. With physicians,  pharmacists, nurses, and other  health care providers working together  to educate the community on the  dangers of secondary smoke to children,  a tremendous impact can be  made on the number of children  exposed to ETS. 

1. American Lung Association. Asthma and Children Fact Sheet. Available at: 

2. American Lung Association. Secondhand Smoke Fact Sheet. Available at: 

3. University of Pittsburgh Medical Center. Patient Education Materials: Smoking and Your Lungs. Available at: 

4. Vargas PA, Brenner B, Clark S, Boudreaux ED, Camargo CA Jr. Exposure to environmental tobacco smoke among children presenting to the emergency department with acute asthma: a    multicenter study. 

5. Wikipedia contributors. Smoking ban. Wikipedia, The Free Encyclopedia. Available at: 

http://en.wikipedia.org/wiki/Smoking_bans

6. Halterman JS, Fagnano M, Conn KM, Szilagyi PG. Do parents of urban children with persistent asthma ban smoking in their homes and cars? 

7. Meltzer SB, Hovell MF, Meltzer EO, Atkins CJ, de Peyster A. Reduction of secondary smoke exposure in asthmatic children: parent counseling. 

8. Schuster MA, Franke T, Pham CB. Smoking patterns of household members and   visitors in homes with children in the United States. 

9. Polanska K, Hanke W, Ronchetti R, et all. Environmental tobacco smoke exposure    and children's health. 

 Ms. Norwalt is a 2008 PharmD candidate  and Dr. Isaac is a clinical assistant  professor of pharmacy at Xavier  University of Louisiana College of  Pharmacy, New Orleans.