So your doctor says you should have a colonoscopy. Knowing how to prepare and what to expect will help you feel more comfortable.
The procedure involves threading a thin tube (the colonoscope) inside you to look for any problems or diseases of the anus, rectum and colon.
Your doctor may suggest this test if you:
- Are between the ages of 50 and 75
- Are younger than 50 and have a personal or family history of colon cancer or polyps or some other risk factors for colon cancer
- Have had:
- Rectal bleeding
- Change in bowel habits such as diarrhea or constipation
- Blood or pus in stool
- Stomach pains
- Iron deficiency anemia
- Abnormalities in certain x-rays of the bowel
- Polyps or tumors in the colon
The safety and effectiveness of a colonoscopy depend on how well your colon is cleansed beforehand. Poor preparation can make it hard to see lesions or get tissue samples for testing. It can also make the procedure take longer or trigger complications. Sometimes, the doctor will even have to cancel the test.
When you schedule the test
Give your doctor a complete list of all the prescriptions, over-the-counter drugs, herbals and supplements you're taking. Tell your doctor if you have any allergies. Also discuss any heart, lung or other medical conditions that may require special attention before, during or after the test.
Check with your doctor before the test if you are diabetic or have any heart conditions. Also, check to see if it is OK to take your other medicines the day of the test.
- You may need to stop taking any aspirin, non-steroidal anti-inflammatory drugs or other blood-thinning drugs several days to a week before the colonoscopy. Check with your doctor for specific instructions.
- If you have diabetes and take insulin, you might need to cut your insulin dosage on the morning of this test. This is because you will not be allowed to eat before the procedure.
Be sure you have someone to take you to and from your colonoscopy. You'll be getting a sedative to make the procedure more comfortable. The effect may not wear off until later in the day, so you shouldn't drive.
The prep will help empty your colon.
Your doctor will give you a schedule to follow the day before the test. A sample schedule may include:
- Have only breakfast and a light lunch.
- Finish eating by 2 p.m.
- Drink only non-carbonated, non-citrus clear liquids until three hours before the test. Broth, sports drinks or gelatin may be options if they are not red.
- Start drinking the solution or taking the laxative pills, enemas or suppositories to flush waste out of your colon.
Carefully follow the instructions that your doctor gives you. This will help ensure your test is safe and the results are accurate.
To cleanse your colon, special solutions may be used. Other preparations may include tablets, enemas or suppositories. Get specific instructions from your doctor about what to take how much to take and the timing. Also ask what you should do if you start to feel nauseous or bloated during the preparation.
You should stay near a bathroom once you start the bowel prep. It usually takes four to six hours to completely empty your colon. You may feel some cramping and discomfort. Call your doctor if you have any pain or have any other problems.
Having a colonoscopy is not something that people look forward to. That's why it's best to prepare properly. That way you have the best chance that the test won't need to be repeated.
Created on 01/02/2009
Updated on 06/01/2012
- Agency for Healthcare Research and Quality. Screening for colorectal cancer.
- Wexner SD, Beck DE, Baron TH, et al. A consensus document on bowel preparation before colonoscopy: Prepared by a task force from The American Society of Colon and Rectal Surgeons (ASCRS), the American Society for Gastrointestinal Endoscopy (ASGE), and the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES). Gastrointestinal Endoscopy. 2006;63(7);894-909.
- American Gastroenterological Association. Preparing for a colonoscopy.