12 Times Aspirin Won’t Work—and Could Be Dangerous

A daily aspirin regimen sounds healthy, but aspirin can be dangerous for people with certain conditions and in certain situations. Find out when this over-the-counter medication won't help and could actually land you in the emergency room.

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Scrutinizing aspirin’s benefits

You know that aspirin can ease pain; most have heard it can prevent heart disease. However, it turns out that only a small group of people get the heart benefits. “Years ago it was common practice to tell most patients to take an aspirin—you know, an aspirin a day keeps the doctor away,” South Florida cardiologist Adam Splaver, MD, says. “Well, this old adage may not only be wrong in some cases; it may send you to the emergency room.” Check out 49 more secrets your pharmacist won’t tell you.

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Over-the-counter does not equal safe

Because you can buy aspirin as an over-the-counter medication, you probably assume it’s safe. “We all have battled some sort of a backache, headache, or knee pain in our lives, and most of us simply pop a few OTC pain relievers to ease the discomfort we are feeling,” says Vernon Williams, MD, sports neurologist and director of the Center for Sports Neurology and Pain Medicine at Cedars-Sinai Kerlan-Jobe Institute in Los Angeles, California. “Doing that seems harmless enough, right? After all, we think, if it’s sold at the local grocery store, it must be safe.” Read about 9 times when another OTC pain medication could cause serious problems.

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If you have a bleeding disorder

If you have ever been diagnosed with a bleeding disorder, steer clear of aspirin. “People with bleeding disorders should avoid taking aspirin, as it is a blood thinner,” says Hoag Medical Group physician Elizabeth Yanni, MD. “Taking aspirin can lead to extreme blood loss and can be fatal.”

Aspirin keeps blood from clotting, and for some people that can turn a small cut into a serious problem. “Aspirin decreases platelet ‘stickiness’ by inhibiting the enzymes that initiate the sequence necessary for platelet activation,” says gastroenterologist Niket Sonpal, MD, associate program director of the internal medicine residency at Brookdale Hospital Medical Center in Brooklyn, New York. “Without platelets, we bleed for longer.”

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If you have a history of stomach problems

If you have frequent stomach pain or ulcers, you need to skip aspirin. “People with a history of stomach ulcers or GI problems should also avoid taking aspirin, as it can lead to ulcer bleeding,” explains Dr. Yanni. This is because aspirin interferes with our stomach’s ability to protect itself.

“The gastrointestinal mucosa uses enzymes to generate the lining and mucus layer that protects us,” Dr. Sonpal says. “Aspirin doses as low as ten milligrams a day inhibit the very enzymes that generate this lining and ultimately yield stomach ulcers.” Check out these 8 proven ways to manage chronic pain without medication.

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If you are taking certain prescription medications

Even common medications like aspirin can lead to serious prescription drug interactions. “Consult with your physician before combining aspirin with any other prescription medications,” Dr. Yanni recommends. “For example, the combination of aspirin and antidepressants can increase the risk of upper-GI bleeding and can be fatal.”

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If you’re planning to have a few drinks

If you’re heading out to a bar or party, pass on the aspirin. Both alcohol and aspirin can exacerbate bleeding, which is why combining them is never a good idea. The combination can also lead to a much quicker rise in your blood alcohol level. According to a study in the Journal of the American Medical Association, taking 100 milligrams of aspirin one hour before drinking can cause a much higher blood alcohol concentration than if people drink the same amount without aspirin. Never combine these drugs and foods.

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If you have asthma

Anti-inflammatory medications like aspirin can cause some serious problems if you have asthma. According to a study in the Journal of Allergy and Clinical Immunology, these medications cause bronchospasm, or a tightening of your breathing muscles, leading to a condition called aspirin-exacerbated respiratory disease.

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If you have high blood pressure

Having high blood pressure can put you at a higher risk for stroke. A hemorrhagic stroke is caused by bleeding in the brain, and that’s why adding aspirin to the mix is dangerous. (An aspirin regimen may be recommended for people who have had an ischemic stroke caused by a clot, however.) Learn the best OTC medication for every type of pain.

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If you’re not a label reader

Even though aspirin is available without a prescription, take the directions seriously. According to a survey conducted by the American Gastroenterological Association (AGA), we’re not as careful as we should be with over-the-counter medications. “More than one quarter of chronic-pain sufferers said they are willing to take more of an OTC pain medicine than directed because they believe it will provide faster and stronger relief,” says Dr. Williams. “This mistake can be a deadly one because it places the user at risk for serious side effects from a potential overdose, including liver damage, ulcers, and even death.”

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You develop an allergy

Pay attention to how you feel after taking aspirin, since many of us tend to ignore minor allergic reactions. These reactions are not limited to aspirin, either. “I’ve seen a number of patients who have developed an allergy to anti-inflammatory medicines, including Advil, Motrin, etc.—the whole family of NSAIDS,” says Dr. Yanni. “People who have the allergy may experience a variety of symptoms, including hives, feelings of your throat closing, itchiness, and more.” Avoid these other 10 medication mistakes that hurt your health.

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If you are under 18 years old

Aspirin use in kids is never safe, so talk with your pediatrician about a better option. “The use of aspirin in children is essentially contraindicated due to the association of aspirin with Reye’s syndrome, particularly if given to children with influenza or varicella,” says Dr. Sonpal. Reye’s syndrome causes swelling in the brain and liver damage. “It’s a rapidly progressive encephalopathy. Symptoms may include vomiting, personality changes, confusion, seizures, and loss of consciousness,” Dr. Sonpal says.

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If you forget to tell your doctor

Because aspirin can interfere with some of your prescriptions or supplements, always tell your doctor if you’re taking it. “Some patients experiencing chronic pain try to manage it on their own without consulting a doctor,” says Dr. Williams. “This mistake is one that I encounter often while seeing patients. They simply think they can ‘handle it’ and save time out of their busy day by not talking to their doctor about what they’re taking.” Dr. Williams recommends discussing all over-the-counter medicines, including aspirin, with your doctor. Make sure you know these other 17 medication mistakes that could make you sick.

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If you take more than you should

Less is more when it comes to aspirin. “Self-medicating should not be taken lightly,” Dr. Williams warns. Almost every OTC pain reliever comes with a warning that whatever ailment you are taking the medication for, if it’s for an extended period of time, you should always consult your doctor, he adds. Many of us may not recognize the symptoms of an aspirin overdose, so stick to the recommended dose.

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If you are taking cold medication

According to the AGA survey, 79 percent of individuals who regularly took pain medications like aspirin also used over-the-counter remedies for cold and flu. “This significantly increases the risk of adverse effects, especially in people with heart disease, high blood pressure, diabetes, asthma, and kidney or liver problems,” Dr. Williams explains. Don’t miss the best cold and flu medicine to always have handy.

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How to stay safe

Although aspirin side effects and complications can be severe, there are times when it is worth the risk. “It seems that only people with a history of cardiovascular disease, stroke, peripheral vascular disease, as well as a small subset of people with atrial fibrillation, or a funny heart rhythm, should be taking this remedy; for them, the benefits outweigh the risks,” Dr. Splaver explains. Your doctor can help you make the right decision for you and your health. Check out 24 secrets pain doctors won’t tell you.

Carrie Madormo, RN, MPH
Carrie is a health writer with a master’s degree in public health who specializes in nutrition, food, and lifestyle for longevity. As a former nurse, she spent a decade working with patients in pediatrics, chronic pain, oncology, occupational health, and public health. She now brings that expertise into digital and print content for outlets such as Health.com, The Healthy, Reader’s Digest, Verywell Health, Taste of Home, Yahoo News, Healthline, Working Mother, and more.