Medications to Stop Before a Colonoscopy

Many people take prescribed or over-the-counter medications they must stop using before a colonoscopy. It proves important to comply with these drug restrictions, and if not, it proves crucial for people to tell their doctor they took a drug on the must-stop list. This is true even if they already had the induced-diarrhea from the bowel preparation and feel as if they should just go ahead with the procedure anyway. Nevertheless, it's better to feel embarrassed or annoyed by reporting they took blood thinner than risk bleeding excessively during a colonoscopy.

Some medications and supplements must be stopped before colonoscopy.

Nonsteroidal Antiinflammatory Drugs

Nonsteroidal antiinflammatory drugs--NSAIDs--should be stopped about four days before the colonoscopy, according to advice from the University of Connecticut Health Center. There are many over-the-counter--OTC--and prescribed NSAIDs, such as naproxen, ibuprofen, indomethacin, ketoprogen, meloxican, nabumetone and piroxicam. If patients have pain that flares up, they can use acetaminophen instead.


According to David C. Dugdale, III, M.D. in his update of the MedlinePlus entry on colonoscopy; patients should iron for several weeks before the colonoscopy because iron residue can produce a dark stool. Even a cleaned-out bowel may become obscured by iron residue, thus making it harder for the doctor to visualize the bowel during the colonoscopy, with the potential risk that something could be missed.

Another reason for stopping iron is that iron can cause constipation, making it more difficult for the bowel cleanser to work.

Note that many vitamin pills contain iron, so patients should stop vitamin pills as well.

Anti-Platelet Drugs

Anti-platelet drugs should be avoided about seven days before the colonoscopy, because they could increase the risk for bleeding during the procedure, notes University of Connecticut Medical Center. Aspirin is one example of an anti-platelet drug and it becomes important to note that many drugs contain aspirin--so check the bottle if a medication is an OTC drug. If prescribed, people ask their pharmacist if any of their medications contain aspirin as an ingredient. If so, then they should ask their physician whether they should stop taking the drug before the colonoscopy.

Other examples of anti-platelet drugs include dipyridamole, pentoxyiflline and tirofiban.


Anticoagulants slow blood clotting and can be dangerous to take before the colonoscopy in the event the doctor must remove one or more polyps or take any action that increases the risk for bleeding, states University of Connecticut Medical Center. Generally, patients should stop these drugs four days before the colonoscopy, but they should ask the prescribing doctor how many days before the procedure they should stop taking them.

Examples of anti-coagulants include warfarin, Coumadin and heparin.


Some supplements should be avoided for at least a few days before the colonoscopy. For example, both vitamin E and chamomile may thin the blood and could cause excessive bleeding during the procedure. Some doctors recommend stopping all vitamin and herbal supplements for a week before the procedure, rather than singling out vitamins or supplements by name.

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