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More Information on Colonoscopy


This information is intended only to provide general guidance. It does not provide definitive medical advice. It is important that you consult your doctor about your specific condition.

What is a colonoscopy?

During colonoscopy, your doctor inserts a thin, flexible tube called a colonoscope into the anus and rectum and slowly advances this tube into the colon (the large intestine). The tube is the same thickness as your finger and has a lens and light source to allow your doctor to view the images on a video monitor. All colonoscopy procedures are performed at the Manhattan Endoscopy Center which is located near our New York City office.

What are the reasons to do a colonoscopy?

Screening for colon cancer is the most common reason to do a colonoscopy. Colon/rectal cancer is one of the most common cancers. With 140, 00 new cases and about 50, 000 deaths every year in the United States, it is the third most common cause of cancer death in both men and women. Increased screening could save about 30, 000 lives every year. The chances of getting colon cancer are much reduced by having a colonoscopy periodically. Colonoscopy is also done to evaluate chronic diarrhea, rectal bleeding, or iron deficiency anemia.

How is the patient prepared for a colonoscopy?

Your doctor will give detailed instructions about dietary restrictions and laxatives that you will need to take. The preparation usually involves avoiding leafy and fibrous vegetables and seeds for a few days, then limiting your diet to clear liquids the day before and drinking special oral laxatives. On the day of the colonoscopy, you cannot eat or even drink any liquids for 3-4 hours before the procedure. The colon must be completely cleaned out in order to have an accurate and thorough examination, so it is important to carefully follow the instructions.

Should I take my regular medications?

You should make sure your doctor knows all the medications you're taking, including non-prescription medicines. Most medications can be continued (especially blood pressure, heart, lung, and seizure medications), but certain medications can interfere with the preparation or the colonoscopy itself, particularly aspirin, arthritis pain medicines, blood thinners (anticoagulants), clopidogrel (Plavix), diabetes medications, iron-containing pills, and vitamins. You should not stop any medications unless you have been instructed to do so by your doctor. You should make sure that your doctor is aware of any allergies to medications.

What will I experience during the colonoscopy?

Colonoscopy rarely causes pain and is usually well tolerated. You will be sedated and asleep during the procedure and should not expect to feel any pain or discomfort. You will be lying on your side while the doctor slowly advances the colonoscope through your large intestine and then slowly withdraws the scope, observing the lining of the colon along the way. You may feel some mild bloating or gas discomfort after the procedure that resolves after you pass gas. Polyps that are found are usually removed during the colonoscopy; this does not cause any discomfort. If any abnormality is seen, your doctor may pass a thin instrument through the colonoscope to take a biopsy (a very small sample of the lining of the colon), which is then analyzed in the laboratory. If bleeding is the reason for the colonoscopy, your doctor may control the bleeding site by injecting medication, cauterizing, or applying small clips. The sedation wears off quickly, and you can eat normally afterward. The procedure usually lasts about 30 minutes, but you should plan to be at the endoscopy center for about 2 hours for waiting, preparation, and recovery. In the unusual event that the scope could not be passed through the entire colon, you may require additional testing.

What can I expect after a colonoscopy?

You will be observed in the recovery room until the sedation has mostly worn off. You might have some abdominal cramps or bloating because air is introduced into the colon during the examination. This goes away after you pass gas. Your physician will explain the results of the colonoscopy to you, but the biopsy results take 4-7 days to become available. You should have an escort to take you home and stay with you; you should not leave alone, even if you are not driving. Even if you feel alert, your judgment and reflexes may be diminished for the rest of the day. You should be able to eat normally after the colonoscopy. Your doctor will instruct you about what medications you can take.

What complications may occur after a colonoscopy?

Colonoscopy and polypectomy are generally safe when performed by doctors who are specialists and have experience. One rare complication is a perforation, or tear, of the colon wall; this would require surgery. Bleeding might occur after polypectomy, but it's usually minor. The bleeding may stop on its own or be controlled with another colonoscopy. Some patients might have a reaction to the sedatives or complications of heart or lung disease. Although complications after colonoscopy are uncommon, it is important to call your doctor if you experience severe abdominal pain, fever and chills, or rectal bleeding. Bleeding can occur up to 10 days after the procedure.

Despite these considerations, colonoscopy is an invaluable diagnostic tool that has saved countless lives.

To learn more about the colonoscopy services offered by Dr. Harary, please contact our New York City office.


Albert M. Harary, MD
110 East 55th Street, 17th Floor
Midtown East/Upper East Side

New York, NY 10022
Phone: 212-702-0123

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