Q&A: Daily Aspirin for Heart Protection

Q: My doctor suggested that I take aspirin every day because it is protective of the heart. I don’t like to take drugs, but he said a low dose was safe. I assume you are against aspirin because it is a drug, but I would like to know for sure. He was very convincing. I believe other readers would be interested in what you think about this. Thank you in advance.

A: I’m with your doctor on this. Aspirin is an excellent, inexpensive therapy, and its cardiovascular benefits are backed by hundreds of studies and decades of clinical use.

Large clinical trials spanning many years have found that for people who’ve had a heart attack, stroke, or TIA (“mini-stroke”), low-dose aspirin reduces the likelihood of a repeat cardiac event. It’s also useful in primary prevention—it lowers risk of a first heart attack in men and stroke in women (except those with diabetes, according to recent research). In addition, aspirin improves outcomes when taken during a heart attack or after angioplasty or bypass surgery.

Of course, aspirin isn’t for everyone. Some people are allergic to aspirin, and the drug can cause stomach ulcers and sometimes severe gastrointestinal (GI) bleeding, particularly when taken in larger doses.

Although it protects against ischemic stroke, it slightly increases risk of the less common hemorrhagic stroke, so it shouldn’t be taken by anyone with a bleeding disorder. Nor should it be taken during viral illnesses—especially by children and teens—because it is associated with potentially fatal Reye’s syndrome.

Last but not least, aspirin interacts adversely with some drugs, so it’s best to talk to your doctor first if you’re taking any medications. (For example, it increases the activity of blood thinners such as Coumadin, and its cardiovascular benefits are negated by ibuprofen.)

So, how much should you take? The recommended dosage of aspirin ranges from 81 mg (the amount in baby aspirin) to 325 mg daily. I usually suggest starting at the low end to minimize potential GI effects. However, a fair number of people do not respond to aspirin’s protective effects at low dosage levels. “Aspirin resistance” affects about a quarter of the population with cardiovascular disease. Whether this is due to diabetes, genetic variations, or advanced disease is unknown. However, it’s clear that not everybody metabolizes aspirin the same way. An effective dose for me might not be enough for you, or it might be too much and cause bleeding.

A company called AspirinWorks offers a test that measures urine levels of a metabolite of thromboxane, which is the target of aspirin. This test will detect any degree of aspirin resistance and help you determine your proper dose. Talk to your doctor about the test, or find out how to order it yourself at aspirinworks.com. — JW

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