The People's Perspective on Medicine

Can Stopping Aspirin Suddenly Lead to Deadly Blood Clots?

Is aspirin a wonder drug or has it been overhyped? Does stopping aspirin suddenly increase the risk for heart attacks or strokes? Can you stop ASA safely?
Aspirin asa pain reliever

Aspirin gets very little respect from health professionals or patients these days. That may be partly because: 1) it’s really old. Aspirin has been around for more than 100 years. 2) Americans prize shiny new objects. 3) Aspirin is available over the counter. That makes it seem less powerful than prescription anticoagulants. 4) Aspirin is inexpensive. At pennies a pill, it lacks the wow factor of pricey blood thinners advertised on television. News articles have recently made it seem as if aspirin is not very helpful in preventing blood clots and could be dangerous. As a result, many people are stopping aspirin suddenly on their own. Are there unrealized dangers?

A Reader worries About Stopping Aspirin Suddenly:

Q. Some years ago I read an article that said not to discontinue daily aspirin use suddenly. The authors of this research warned that people were having strokes when they stopped taking aspirin two weeks before a surgery. I worry that blood clots could form if people stop taking long-term aspirin use too quickly. Have you heard of this?

Stopping Aspirin Suddenly Before Surgery?

A. There is a surprising amount of controversy surrounding the question of stopping aspirin. Some doctors recommend discontinuing aspirin three days before surgery. Others tell patients to stop it five to ten days prior to any surgical procedure.

Many patients stop aspirin on their own without even consulting the surgeon or anesthesiologist. Scary headlines about aspirin dangers are also leading to people stopping aspirin suddenly.

We discourage that approach. It is important to get a clear recommendation from the people who will be performing the surgery. If a doctor has recommended aspirin as part of a heart or stroke protection plan, do not stop without consulting her. 

Does Stopping Aspirin Suddenly Pose Risks?

A Swedish study involving over 600,000 patients concluded that:

“In long-term users, discontinuation of low-dose aspirin in the absence of major surgery or bleeding was associated with a greater than 30 percent increased risk of cardiovascular events” (Circulation, Sept. 26, 2017).

The authors speculate that a rebound effect may occur after aspirin discontinuation. In other words, there may be an increased risk of blood clots after stopping aspirin. If it exists and how long it might last is uncertain and remains controversial. 

A reader of our syndicated newspaper column wrote to us after reading about a woman who had experienced a heart attack after stopping aspirin suddenly.

She wrote to tell us that in 2015 she was told to stop aspirin a week prior to shoulder replacement surgery. A few days before the surgery she had an ischemic stroke (caused by a blood clot). Was it caused by discontinuation of aspirin. We’ll never know. Here’s a similar story.

How Can You Prevent Blood Clots in the Legs?

Brad in Honduras shared this story about a dangerous DVT (deep vein thrombosis)

“I took aspirin for 25 years and stopped for a month. That was when I took a long trip (over20 hours). I drove continuously, only stopping for gas. I developed DVT in my leg and am now on blood thinners which they tell me is for life. I wondered if that was partly the cause.”

It is almost impossible to say what caused the blood clot to form in Brad’s legs. Long trips are notorious for triggering DVTs. That holds for car rides as well as airplane trips. Would the aspirin have prevented the clot? Perhaps.

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You can read about ways to prevent DVTs at this link:

Blood Clots, Travel and Deep Vein Thrombosis (DVT)

What About Bleeding After Staying on Aspirin?

Let’s not forget the flip side of this coin. Aspirin does have anti-platelet activity. That means the blood is less likely to clot. Readers have reported scary bleeding episodes after continuing on aspirin during surgical procedures.

Catherine in Washington had just such an experience:

“I meant to go off aspirin before my last colonoscopy. I simply forgot. I take adult-strength aspirin for joint and muscle pain. Aspirin helps me sleep.

“A polyp was removed during the colonoscopy. When I got home home, I began bleeding and lost a pint and a half of blood before the bleeding stopped. It took a day and a half for the bleeding to quit. It was very frightening.”

The Horns of a Dilemma:

People feel conflicted about the messages they are getting about aspirin. On the one hand there are studies that say aspirin can cause dangerous bleeding episodes and the benefits aren’t that great. On the other, they are told that stopping aspirin suddenly may lead to dangerous blood clots. There are no clear guidelines about how to phase off aspirin gradually. That is why some readers are feeling very frustrated.

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Lamar in Texas shares this thought.

“I was told to take aspirin along with my other medications after I had by-pass surgery. There was no damage to the heart muscle. After 22 months I learn that the aspirin might kill me if I stop it suddenly. There is a risk of a heart attack or a stroke. But if you keep taking aspirin you may bleed and that could lead to death. 

“I wouldn’t have taken aspirin in the first place if I had known that. Why don’t doctors and pharmacists tell you about this before they recommend a drug like aspirin?”

The Pros and Cons of Aspirin:

To put the benefits and risks of aspirin into perspective, here is an article we have written on this topic.

Should You Take Aspirin for your Heart? Does Your Doctor Know for Sure?

Share your own thoughts about stopping aspirin suddenly in the comment section. Anyone who considers stopping aspirin should discuss the plan with a health professional. Some people may need to stay on aspirin indefinitely. Others may need a very gradual withdrawal regimen. It is surprising there are still so many unanswered questions for a medicine that has been around for more than 100 years.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
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  • Sundstrom J et al, "Low-dose aspirin discontinuation and risk of cardiovascular events: A Swedish nationwide population-based cohort study." Circulation, Sep. 26, 2017.
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When you use % please consistently identify absolute or relative.

Good point. We will strive to do so.

Are you saying you’re taking six 325 mg tablets every day? Standard opinion says that will eat a hole in your stomach!

Most of us on a daily 81 mg aspirin are running the experiment each time we suspend taking the aspirin when we have one of the procedures when the doc tells us to suspend. We go cold turkey for several days before the procedure, and the aspirin will be gone from our systems at some point.

Please do not forget the study with colon polyps and baby aspirin. The baby aspirin users had NO polyps, and they were polyp prone. It was a nation-wide study. Will continue taking a baby ASA.

thanks for the reply..makes sense..complex topics and remedies not the same for everyone and you try and cover all aspects which sometimes leaves the reader a bit bewildered but does contain a lot of good info too… thanks for your continued efforts to get all the info out and keep up the good work!

One of your most confusing and worry causing articles ever with no clear answers, as usual. Where’s the benefit for the readers? (just more worry and confusion).


If there were simple or easy answers to this dilemma we would have provided them. There are some things in medicine that are extremely complex. Trying to come up with a universal answer for everyone is often impossible. That is why in this and many other situations the best path has to be individualized for each person working in partnership with a knowledgeable health care provider.

To be specific, a person’s genetic profile is important. So are the medicines he or she is taking. Then there are the background risk factors. Is the person more likely to bleed (aspirin would be a non starter) or clot (aspirin might be better). We wish there were easy answers that would allow us to make recommendations for everyone. Such is not the case with aspirin.

Does aspirin dose matter when it comes to increased bleeding or dangers after discontinuing? Is there a difference between taking baby aspirin 81mg daily versus 325mg? As usual, the devil could be in the details.

I’m a frequent donor of blood and platelets. I’ve been taking a daily baby aspirin for many years but must stop for three days before donating. Based on reports in the Peoples Pharmacy I’ve been wondering whether at age 77 I should continue with the aspirin. I asked my doctor, and he said I should continue. Now I’m thoroughly confused. Should I keep donating?

I read years ago to take your low dose aspirin before you go to bed. Is there any truth to this or does it even matter if you take it in the morning when you wake up or before you go to bed?

I under went a Watchman Device implant and did several months of Warfarin and Plavix therapy for Left Atrial clotting. My long term Aspirin was withdrawn during the therapy. Within one month of discontinuation of the therapy I had a clot-caused stroke. A few years ago there was concern of a rebound on clotting after discontinuance of Plavix. It was poohed-poohed and still is. There seems to be a big problem in not researching this. The Watchman Device manufacturer should be required to research it. A device that was supposed avoid 60% of stokes due to one origin of clots should not have caused others. I would have been better off on warfarin therapy which is a systemic all-cause therapy.

I’m confused. My whole life I’ve used aspirin when needed for headache, fever or pain, thus not daily. What is the impact on people who use aspirin this way? Does it also increase the risk for strokes, etc. or is that just for those who were taking it daily?

We think the rebound effect is only for people who take it daily.

Aspirin is a fantastic alternative to overpriced blood thinners. Remember never to take it on an empty stomach.

Could the Swedish study also be showing that aspirin actually lowers the risk of cardiovascular issues, and by discontinuing aspirin you have the same risk as if you never took aspirin long term in the first place?

I once stopped taking aspirin a few days before a colonoscopy. As it happened, during one of the days I was off aspirin, I had the first of a series of three blood tests from Boston Heart Health that compared various results over time. One of the tests was for levels of fibrinogen, which I understand has a connection to blood thickness. The test showed that I had dangerously high levels of fibrinogen. However, the next two tests (when I was taking aspirin) showed that the levels were normal. While this may be a coincidence, I don’t think so. I believe the tests showed that aspirin is keeping my fibrinogen levels normal.

An important context for this story is that I’ve been taking at least six 325-mg tabs of enteric-coated aspirin for over 30 years. Even though it’s coated, I take the aspirin with food. Another important context: I have bicuspid aortic valve, and people my age with BAV tend to have higher levels of calcification than normal (and tend to need replacement of the aortic valve). I had a heart calcification test a few years ago that showed I was in the lowest 5% in my age group for heart calcification. My cardiologist told me last year that I probably won’t need surgery for 10 years, and at that time, they’ll be able to replace the aortic valve through an artery rather than surgery.

Bottom line, I’m very thankful for aspirin and wouldn’t want to stop taking it.

I don’t give too much credence to the “experts” any more. About 100 years ago they also said butter was really bad and would clog vessels. So all America quit using butter and ate Margarine. Then 100 years later they told us that was all bogus. Truth is good, but lies hurt.

Wow… the experts may be entertaining. But they’re sometimes not very smart. I’m staying on my daily babyaspirin regimen.

Is there any research about simply cutting back on aspirin, since it remains in the system for more than one day? I’ve taken aspirin 81mg every day for 15 years with no problems. When this contoversy began I talked with my doctor, and we decided twice a week should work well. Have been using aspirin twice a week for 3 months with no events.

I had a heart attack caused by a random blood clot (no family history, no risk factors) six years ago, and as a result am on a regimen of daily low-dose aspirin. Since then I have had several surgeries and procedures, including a partial colectomy and a
diagnostic heart cath, stayed on my aspirin through all of them, and haven’t bled to death yet. Let’s hope that trend continues!

My husband’s Cardiologist has replaced aspirin 325 with Coumadin after 20 years and he is having side effects. He is 86. I fail to see the benefits.

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