The Food and Drug Administration (FDA) is warning people that a daily aspirin regimen may not help prevent a heart attack or stroke, and may cause dangerous bleeding into the brain or stomach.

Although a daily low dose of aspirin has been shown to be effective in preventing a reoccurrence of a heart attack or stroke, the FDA is now warning people who have not had a first heart attack or stroke that taking an aspirin every day may not have a benefit. In fact, doing so may actually cause serious side effects.

Robert Temple, M.D, deputy director for clinical science at the FDA, said in a Consumer Update, “Since the 1990s, clinical data have shown that in people who have experienced a heart attack, stroke or who have a disease of the blood vessels in the heart, a daily low dose of aspirin, used as secondary prevention, can help prevent a reoccurrence.” A regular strength tablet is 325 milligrams (mg). A low-dose table is 80 milligrams (mg).

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However, following examination of scientific data from major studies, the FDA has concluded that the data do not support the use of aspirin as a preventive medication by people who have not had a heart attack, stroke, or cardiovascular problems, a use that is known as primary prevention. In these people, the benefit has not been established, and risks, such as dangerous bleeding into the brain or stomach, are still present.

Temple advised that daily aspirin therapy should be used only after you talk to your healthcare provider, who can weigh the benefits and risks.

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A heart attack occurs when one of the coronary arteries, which provide blood to the heart, has developed a clot that obstructs the flow of blood and oxygen to the heart. Aspirin works by interfering with your blood’s clotting action.

The FDA is also recommending that people be careful when using aspirin with other blood thinners, such as warfarin, dabigatran (Pradaxa), rivaroxaban (Xarelto) and apixiban (Eliquis).

Andrea Fass, Pharm.D., assistant professor of pharmacy practice at Nova Southeastern University, told Healthline, “Taking aspirin with blood thinners can increase the risk of bleeding. In some patients it may be necessary to take them in combination, but that should always be determined by their healthcare provider. I manage patients who take warfarin, and we do have some patients who are on aspirin because they have had either a significant heart attack or a blockage. But just for prevention it may not necessarily be the best thing for them. You have to look at the patient’s risk to determine if it is appropriate. They need to be evaluated to determine their bleeding risk.”

Fass went on to say some individuals may not be the best candidates for aspirin therapy, such as those who have a history of any type of ulcer. A person may have such low risk that aspirin may not be something they need. “As we get older, risk for heart attack or stroke definitely does increase. If you are very young and healthy and taking aspirin, it may not be something you have to do. It also depends on other medications you are taking. If you are taking medications that aren’t blood thinners, they could also be very hard on the stomach and could potentially increase the risk of stomach bleed, as well.”

Finally, acknowledging that aspirin “is a great medication,” Fass said, “Many times we assume that over-the-counter medications are all safe because you don’t need a prescription. It’s very important to speak to a pharmacist and your healthcare provider to find out if the medication is appropriate. You always want to weigh the risk versus the benefit with any medication you take.”

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Temple advised that the clinical data do not show a benefit in people who have not had heart problems or a stroke but, because of family history or other evidence of arterial disease, are at increased risk.

The FDA is monitoring a number of ongoing, large-scale clinical studies that are investigating the use of aspirin in primary prevention of heart attack or stroke.

“The bottom line is that in people who have had a heart attack, stroke or cardiovascular problems, daily aspirin therapy is worth considering,” said Temple, adding, “And if you’re thinking of using aspirin therapy, you should first talk to your healthcare professional to get an informed opinion.”

The FDA advises to find out what the correct dose is for you and how often you should take it so you can get the greatest benefit and the least amount of side effects.

Finally, the FDA warns, if your healthcare professional recommends daily aspirin to lower the risk of a heart attack and clot-related stroke, read the labels carefully to make sure you have the right product. Some drugs combine aspirin with other pain relievers or other ingredients, and should not be used for long-term aspirin therapy, according to the FDA.

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