Should I take aspirin? The risks and benefits. Podcast created by Lia Schmitz, Pharm.D. for Island Drug. March 6, 2013

Transcription

1 Should I take aspirin? The risks and benefits Podcast created by Lia Schmitz, Pharm.D. for Island Drug March 6, 2013 Aspirin is one of the oldest medicines, useful as a pain reliever, antiinflammatory, fever reducer, and blood clot preventing agent. Many folks say you are 'supposed' to take it for heart health. It is a powerfully effective and affordable preventative measure, for some people. But it isn't worth while for everyone. This podcast is intended for people who have not had recent surgery or have been diagnosed with a clotting disorder of any sort. Aspirin offers an antithrombotic effect by inhibiting platelets' inclination to clump together. Aspirin irreversibly inhibits an enzyme Page 1 of 5

2 called cyclooxygenase, which is responsible for creating thromboxane A2. Platelets have no nucleus, so can not regenerate these components. Thromboxanes are one of the many pathways responsible for getting platelets to stick to each other in a blood clot. Thus, when you take a dose of aspirin, you permanently knock out a portion of the clotting ability of platelets. A given platelet is only in circulation for eight to ten days. Your body is always making new platelets, so in order to achieve and maintain this effect, you need to take a small dose of aspirin every day for an extended period of time. Aspirin for use as clot prevention is often advised if you have an artificial heart valve, a stent, or a heart condition known as atrial fibrillation. Please discuss this with your doctor because it needs to be coordinated with any other clot preventing medications you have been prescribed. If you have ever had a heart attack or a stroke, even a little one, in the past, you should consider taking aspirin daily, again please discuss with your physician. For those without any existing heart conditions, aspirin is advisable only for some. People 50 years an older will, statistically, reap some benefit from taking 81 mg of aspirin every day. In the long term (10 years), taking this 'baby' aspirin decreases the likelihood of dying from Page 2 of 5

3 a cardiovascular problem. Broadly speaking, aspirin helps prevent heart attack in men, and stroke in women. The US Preventative Service Task Force recommends men start taking it at age 45 and women at age 55. The benefit is greater for those people at more risk of heart disease or stroke. Here are some risk factors: " male " smoker " family history of heart problems " high blood pressure " diabetes " high cholesterol " obesity " lack of exercise " chronic kidney disease People with multiple risk factors are more likely to benefit than those with few or none of these risk factors. There is scattered evidence for other uses of aspirin. It is sometimes used to prevent migraines or depression, and may prevent ovarian, prostate, and colon cancer. It is used to prevent deep vein thrombosis Page 3 of 5

4 and may help prevent dementia in some patients. It is not generally recommended for preventing leg clots in long distance travelers. In addition to the cost and inconvenience of taking a medication every day, aspirin can also cause side effects. It has been known to cause asthma, upset stomach, or a form of swelling known as angioedema. The most serious side effect is stomach bleeding. The propensity to cause stomach bleeds ties back to aspirin's ability to inhibit cyclooxygenase. In addition to creating thromboxane, cyclooxygenase also creates prostaglandin. Prostaglandins help protect the stomach from itself. After all, the stomach is a highly acidic and harsh environment and could digest its own walls if they were unprotected. This decrease in stomach wall protection, coupled with a person's now lesser propensity to clot, can cause a bleeding ulcer in the stomach. Very roughly speaking, a 'major bleed' from aspirin is about a 2% risk, weighted toward those taking larger doses. A bleeding stomach ulcer is a big problem because it not only causes pain, but can lead to a lot of blood loss. Taking enteric-coated aspirin may decrease stomach upset a little, though there is still risk of stomach ulcer. The benefits of decreasing your risk of a cardiovascular incident are closely balance with increasing your risk of a stomach bleed. The elderly are Page 4 of 5

5 significantly more likely to suffer from the stomach ulcer side effects. They are also the ones more likely to benefit from the blood-thinning properties, since they are more at risk of a heart attack or stroke to begin with. If you have zero or only one of the risk factors I listed a moment ago, the risk of stomach bleed may not be worth the marginal benefit to your heart. Prevention of cardiovascular disease, heart attack, and stroke is under intense, long term research. The recommendations may change as new evidence is published, so please check in periodically with your pharmacist or physician. Ridker PM et al. NEJM 2005; 352: Lecture material from Ann Wittkowsky at UW February 2010 CHEST guidelines 2012 from the American College of Chest Physicians, downloaded 7/2/2012important part in lowering blood pressure. Page 5 of 5