Aspirin has long been famous for its role in heart disease prevention and treatment. But for many people, one area of confusion is whether or not it counts as a blood thinner.<\/p>\n
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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy<\/a><\/p>\n So, let\u2019s clear things up right away: Yes, aspirin is a blood thinner.<\/p>\n That means it can help keep blood clots<\/a> from forming spontaneously in your blood vessels. But it works a bit differently than some other blood thinners. And like all meds, even though it has benefits, it carries risks, too.<\/p>\n Interventional cardiologist Rishi Puri, MD, PhD<\/a>, explains exactly how aspirin works and why its use requires the careful guidance of a healthcare provider.<\/p>\n How aspirin thins your blood<\/p>\n Aspirin stops platelets from clumping together to form blood clots. This \u201cthins\u201d your blood and helps reduce the risk that blood clots will form when they ordinarily shouldn\u2019t.<\/p>\n Your blood doesn\u2019t physically get \u201cthinner,\u201d Dr. Puri clarifies. Instead, it can flow more easily through your arteries. \u201cPlatelets are less likely to become spontaneously activated to form a clot within an artery \u2014 or even within a stent implanted in an artery,\u201d he says.<\/p>\n Platelets are cells in your blood that help cause clots to form immediately when you\u2019re injured. \u201cThey act like your body\u2019s natural bandage and are a crucial part of the immediate healing process,\u201d Dr. Puri explains. \u201cBut sometimes, platelets can spontaneously become activated to clump together and form clots at times when you don\u2019t need them. These clots can block blood flow and lead to serious issues, like a heart attack or stroke, or even clog a stent.\u201d<\/p>\n When people use the broad term \u201cblood thinners,\u201d they\u2019re referring either to antiplatelet<\/a> medications or anticoagulants<\/a>. Aspirin belongs to the antiplatelet group. The meds in this group all work by stopping platelets from clumping together.<\/p>\n \u201cAspirin is the most commonly prescribed antiplatelet agent,\u201d he adds.<\/p>\n Anticoagulants, on the other hand, don\u2019t target platelets. Instead, they act in other ways that affect what healthcare providers call the \u201cclotting cascade.\u201d This refers to a series of steps, including enzyme reactions, that need to happen for a clot to form.<\/p>\n \u201cWe use antiplatelet medications and anticoagulants together in certain circumstances,\u201d Dr. Puri further explains. \u201cSometimes, it\u2019s just one or the other. It depends on what we\u2019re treating or trying to prevent.\u201d<\/p>\n Guidelines for use<\/p>\n If your healthcare provider prescribes aspirin for you, it\u2019s crucial to closely follow their guidance. If you skip doses, aspirin may not work as it should. On the other hand, taking too much can lead to dangerous complications, like bleeding (more on that in a bit).<\/p>\n Your provider may advise taking aspirin for:<\/p>\n Primary cardiovascular disease prevention<\/a>: This means you\u2019ve never had a heart attack or stroke and are trying to keep it that way.Secondary cardiovascular disease prevention: This means you\u2019ve had a major cardiovascular event, like a heart attack, stroke or stent placement<\/a>. Now, the goal is to help prevent more events.Heart attack first aid: Aspirin can be lifesaving during a heart attack.<\/p>\n Dr. Puri explains how aspirin can help in each scenario.<\/p>\n Primary prevention<\/p>\n In the past, healthy adults took a baby aspirin a day to help keep heart attacks away. But today, the guidelines are stricter.<\/p>\n \u201cWe only prescribe daily aspirin therapy for people who are at high risk for heart attacks or strokes,\u201d Dr. Puri clarifies. \u201cThis usually means your risk is at least 10% to 15% over the next 10 years. In these situations, aspirin can greatly lower the odds, and the benefits of taking it outweigh the risks of bleeding from it.\u201d<\/p>\n Before going further, a quick terminology check:<\/p>\n The terms \u201cbaby aspirin\u201d and \u201clow-dose aspirin\u201d typically refer to an 81 milligram (mg) tablet.\u201cDaily aspirin therapy\u201d means taking one baby aspirin (low-dose aspirin) every day to support your heart and blood vessel health.Secondary prevention<\/p>\n Aspirin can play a major role in preventing heart attacks and strokes once you\u2019ve already been diagnosed with heart disease. In fact, secondary prevention is the most common reason providers prescribe aspirin, Dr. Puri reports.<\/p>\n \u201cYour doctor may start you on aspirin along with another blood thinner,\u201d he says. \u201cAfter a certain amount of time, they may remove the other medication and just keep you on aspirin going forward. Sometimes, they may do the reverse \u2014 they stop the aspirin and keep the alternate blood thinner going. That\u2019s becoming increasingly common.\u201d<\/p>\n You may also need to take aspirin if you\u2019ve had a tissue valve<\/a> implanted in your heart. This can reduce the risk of clots forming on the valve.<\/p>\n Heart attack first aid<\/p>\n When you\u2019re having a heart attack<\/a>, aspirin can help keep any existing clots from getting bigger. This lets some blood continue to reach your heart.<\/p>\n \u201cDon\u2019t delay calling for help,\u201d Dr. Puri urges. \u201cBut while you\u2019re on the phone, take an aspirin \u2014 not a baby dose, but the full dose of 325 mg. If you don\u2019t have any on hand, first responders will likely give you an aspirin on the way to the hospital.\u201d<\/p>\n Of course, this doesn\u2019t apply if you\u2019re allergic to aspirin. In that case, talk to your provider about the first aid they recommend so you can be prepared.<\/p>\n Risks of taking it<\/p>\n Aspirin can be lifesaving, but it comes with risks, especially when taking it long term. <\/p>\n