Aspirin and medicines such as ibuprofen (Motrin IB, Advil, others) and naproxen sodium (Aleve) may thin the blood. This can decrease blood clotting. Regular use of ibuprofen and naproxen sodium can increase bleeding risks. The medicines, as well as aspirin, also can lead to stomach ulcers. The risk of ulcers goes up significantly if you take aspirin and one of these other medicines together.

Ibuprofen and naproxen are types of drugs called nonsteroidal anti-inflammatory drugs (NSAIDs). Certain NSAIDs increase the risk of heart attacks. Taking aspirin with some NSAIDs can increase the risk of bleeding even more.

If you have a reason to use low-dose aspirin — such as a history of a heart attack or bypass surgery — NSAIDs cannot be used instead of aspirin to prevent heart attacks.

If you need to take ibuprofen or similar medicines, talk to your health care provider about alternatives that won't interfere with daily aspirin therapy. For example, acetaminophen (Tylenol, others) may be an option.

Aspirin affects how blood clots. When a person bleeds, clotting cells called platelets go to the site of the wound. The platelets help plug the opening in the blood vessel. This stops bleeding.

Sometimes such clots occur inside a damaged heart artery. The clot prevents blood flow to the heart and causes a heart attack. Having a condition called atherosclerosis increases the risk of these types of clots.

Since aspirin reduces clotting action, it's thought that daily aspirin therapy could possibly prevent a heart attack.

Yes. Taking aspirin during a heart attack is safe and recommended. If you think you're having a heart attack, call 911 or emergency medical services. Don't delay calling for help. Aspirin alone won't save your life if you're having a heart attack.

When you call for help, the emergency operator may tell you to chew an aspirin. The operator will first ask if you have an aspirin allergy or other health conditions that would make taking an aspirin unsafe. It's OK to chew an aspirin if your health care provider has previously told you to do so if you think you're having a heart attack — but always call 911 or emergency medical services first.

Taking aspirin every day may lower the risk of heart attack and stroke. Yet daily aspirin therapy isn't for everyone. Is it right for you?

The answer depends on your age, overall health, history of heart disease, and risk of heart attacks or strokes.

Daily aspirin therapy may be used in two ways:

• Primary prevention. This means you've never had a heart attack or stroke. You've never had coronary bypass surgery or coronary angioplasty with stent placement. You've never had blocked arteries in your neck, legs or other parts of the body. But you take a daily aspirin to prevent such heart events. The benefit of aspirin for this use has been debated.
• Secondary prevention. This means you've already had a heart attack or stroke, or you have known heart or blood vessel disease. You're taking a daily aspirin to prevent heart attacks or strokes. The benefit of daily aspirin therapy in this situation is well established.

Take daily aspirin therapy only if your health care provider tells you to do so. Before starting aspirin therapy, tell your health care provider about all the health conditions you have.

Daily aspirin therapy may not be a good choice if you have:

• A bleeding or clotting disorder that causes you to bleed easily.
• An aspirin allergy, which can include asthma caused by aspirin.
• Bleeding stomach ulcers or a history of gastrointestinal bleeding.

Coated aspirin also is called enteric-coated aspirin. It is made to pass through the stomach and not dissolve until it reaches the small intestine. Coated aspirin may be gentler on the stomach. It may be appropriate for some people who take a daily aspirin, especially those with a history of gastrointestinal inflammation or ulcers.

But there's no evidence that taking coated aspirin decreases the chance of developing gastrointestinal bleeding. Also, coated aspirin may not work as well as plain aspirin when taken at the time of a possible heart attack. Talk to your health care provider if you're concerned about ways to decrease your bleeding risk.

Don't start taking a daily aspirin without talking to your health care provider. Taking an occasional aspirin or two is usually safe for most adults to use for headaches, body aches or fever. But daily use of aspirin can have serious side effects, including gastrointestinal bleeding.

Talk to your health care provider about the pros and cons of daily aspirin therapy. Together you can discuss whether an aspirin a day might help prevent a heart attack or stroke.

As a person gets older, their risk of heart attack and stroke increases. However, the risk of bleeding from aspirin goes up even more. So:

• In people who have a low risk of heart attack, the benefits of taking a daily aspirin don't outweigh the risks of bleeding.
• The higher the risk of heart attack, the more likely it is that the benefits of daily aspirin therapy are greater than the bleeding risks.

Because of bleeding risks, some guidelines say that people age 60 and older without known heart or blood vessel disease should not start taking a daily aspirin to prevent a first-time heart attack or stroke. However, guidelines vary among organizations. Other recommendations say to avoid starting daily aspirin therapy after age 70.

If you're between ages 60 and 69, ask your health care provider how daily aspirin therapy may affect you.

Daily low-dose aspirin therapy may be recommended for the primary prevention of heart attack or stroke if:

• You're between ages 40 and 59 and you're at high risk of having a first-time heart attack or stroke within the next 10 years. High risk means your risk is 10% or greater.
• You haven't had a heart attack, but you've had coronary bypass surgery or a stent placed in a heart artery, or you have chest pain called angina or any other medical condition where aspirin is proved to prevent heart attacks or stroke.
• You're younger than 60 and you have diabetes and at least one other heart disease risk factor, such as smoking or high blood pressure.

If you've had a heart attack or stroke or you have known heart disease, your health care provider may recommend taking an aspirin a day to prevent heart attacks or strokes unless you have a serious allergy or history of bleeding.

Sometimes, a health care provider might recommend combining low-dose aspirin with a prescription blood thinner. Such combination therapy always needs to be carefully discussed. The combination may greatly increase the risk of major bleeding.

Prescription blood thinners include:

• Apixaban (Eliquis).
• Dabigatran (Pradaxa).
• Enoxaparin (Lovenox).
• Heparin.
• Rivaroxaban (Xarelto).
• Warfarin (Jantoven).

Other medicines that can interact with aspirin and may increase bleeding risks include:

• Clopidogrel (Plavix).
• Corticosteroids.
• Ibuprofen (Advil, Motrin IB, others), when taken regularly.
• Some antidepressants, such as clomipramine (Anafranil) and paroxetine (Paxil, Brisdelle, Pexeva).

Certain herbal and dietary supplements also can increase the bleeding risk when combined with aspirin. These include:

• Bilberry.
• Capsaicin.
• Cat's-claw.
• Danshen.
• Evening primrose oil.
• Ginkgo.
• Kava.
• Ma-huang.
• Omega-3 fatty acids (fish oil).

Drinking alcohol while on daily aspirin therapy may increase the risk of stomach bleeding. Talk to your health care provider about how much alcohol is safe to drink. If you choose to drink alcohol, do so in moderation. For healthy adults, that means up to one drink a day for women and up to two drinks a day for men.

Side effects and complications of taking daily aspirin include:

• Stroke caused by a burst blood vessel. While daily aspirin can help prevent a clot-related stroke, it may increase the risk of a bleeding stroke. A bleeding stroke also is called a hemorrhagic stroke.
• Gastrointestinal bleeding. Daily aspirin use increases the risk of developing a stomach ulcer. If you already have a bleeding ulcer or gastrointestinal bleeding, taking aspirin may cause more bleeding. The bleeding may be life-threatening.
• Allergic reaction. If you're allergic to aspirin, taking any dose of aspirin can trigger a serious allergic reaction.

If you're taking aspirin and you need surgery or dental work, be sure to let the health care provider know. You and your provider may need to take steps to prevent excessive bleeding. Don't stop taking aspirin without talking to your health care provider.

If you are on daily aspirin therapy, talk to your health care provider before stopping it.

If you've had a heart attack or a stent placed in one or more of your heart arteries, it's important to keep taking daily aspirin and any blood-thinning medicines exactly as told by your health care provider. Stopping daily aspirin therapy suddenly may trigger a blood clot and lead to a heart attack.

You and your health care provider can discuss what aspirin dose is right for you. Low doses of aspirin — such as 75 to 100 milligrams (mg), but most commonly 81 mg — can be effective at preventing heart attack or stroke. Health care providers usually prescribe a daily dose between 75 mg and 325 mg.