Do you need to stop taking aspirin for a colonoscopy?

Aspirin is one of the most common medications that people take on a daily basis. In the US, it is estimated that roughly one-fourth of the population over the age of 45 takes aspirin daily, and in the 65-and-older population this number jumps to almost one-half.

Most people take aspirin to prevent or treat a heart attack, stroke, or for other vascular diseases. For most, aspirin use can be further divided into the following categories: 1) Primary prophylaxis (to prevent the first heart attack or stroke); 2) Secondary prophylaxis (to prevent another heart attack or stroke in a patient with a history of these problems); and/or 3) To “protect” an indwelling vascular device such as a cardiac stent.


As we all know, aspirin can also increase the risk of bleeding somewhat by deactivating platelets. We also know that the entire purpose of a screening colonoscopy is to find and remove polyps to prevent the development of colon cancer. If we are doing it right, that means we gastroenterologists cut out a lot of polyps in our work day. Cutting out polyps can cause some bleeding. Aspirin and bleeding are not the best combo…at least in theory.

With modern endoscopy techniques, virtually all bleeding that may happen during the process of removing a polyp (i.e., immediate bleeding) can be treated and stopped during the procedure. It is the risk of delayed bleeding after polypectomy that worries most gastroenterologists. The risk of delayed bleeding seems to correlate with the size of the polyp, the location in the colon, and the age and medical comorbidities of the patient. When it occurs, delayed bleeding usually happens within 14 days of the procedure, but in some cases can occur up to three weeks after a polyp is removed.

With all this talk about bleeding, it should come as no surprise that “Should I stop my aspirin?” is one of the more common questions that I get asked by patients who are being seen to arrange screening colonoscopy. Luckily, this question has been answered already by several of the gastroenterology societies. For the average patient on aspirin who is about to have a routine colonoscopy, the answer is: No, do not stop your aspirin!

Removing polyps during a colonoscopy while on aspirin is considered safe, and the risk of bleeding after polypectomy has not been shown to be significantly increased in patients taking aspirin when compared to patient not on aspirin. This is true for biopsy polypectomy, cold snare polypectomy, and hot snare polypectomy techniques. Furthermore, in most patients taking aspirin for secondary prophylaxis or to protect a cardiac stent, the risk of precipitating a cardiovascular complication (heart attack, stent thrombosis, stroke) by stopping aspirin seems to outweigh any possible benefit in terms of reducing short term bleeding risk.

I sometimes find myself reminding patients that bleeding after a procedure (which is thankfully a rare event) is unfortunate, scary, and potentially dangerous, but in almost all cases is treatable (usually with another procedure to stop the bleeding). However a heart attack or stroke brought on by stopping aspirin inappropriately is often more scary, and infinitely less reversible.

Since these recommendations have been in place since 2009, it is somewhat unsettling that as of 2014, roughly 32 percent of endoscopy units across the US still have a blanket policy of stopping aspirin for routine colonoscopy. An additional 24 percent of units have a “contact your doctor” policy, with only the remaining 43 percent of units encouraging all patients to continue aspirin as a general policy. So despite good evidence that stopping aspirin is not only unnecessary but also may be harmful, many doctors still do not follow the guidelines.

In conclusion, aspirin should be continued for colonoscopy in almost all patients. The exception is the patient that is already known to have a large polyp (with a high-risk of delayed bleeding) that will need to be removed, and who has a weak indication to be on aspirin in the first place (e.g., primary prophylaxis with very low cardiovascular risk factors). In this specific case, for certain patients, it may be reasonable to stop the aspirin 5-7 days prior to the procedure. But remember, this patient is not your average screening patient: By definition this is a patient that has been scoped before and is now presenting for a therapeutic colonoscopy.

Also if any pre-colonoscopy patients are reading this, it should go without saying, but this information above is for educational purposes only. It is not a substitute for discussing your individual case with your doctor. It is also not a reason to do something other than what your doctor has instructed you!

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Becker RC, Scheiman J, Dauerman, HL, et al. Management of platelet-directed pharmacotherapy in patients with atherosclerotic coronary artery disease undergoing elective endoscopic gastrointestinal procedures. Am J Gastroenterol 2009;104:2903-2917.

Robbins R, Tian C, Singal A, et al. Periprocedural management of aspirin during colonoscopy: a survey of practice patterns in the United States. Gastrointest Endosc 2015;82:895-900.

Standards of practice committee; Anderson MA, Ben-Menachem T, Gan SI, et al. Management of antithrombotic agents for endoscopic procedures. Gastrointest Endosc 2009;70:1060-70.

Image via Yliniemi