How you prepare
Before a colonoscopy, you'll need to clean out (empty) your colon. Any residue in your colon may obscure the view of your colon and rectum during the exam.
To empty your colon, your doctor may ask you to:
- Follow a special diet the day before the exam. Typically, you won't be able to eat solid food the day before the exam. Drinks may be limited to clear liquids — plain water, tea and coffee without milk or cream, broth, and carbonated beverages. Avoid red liquids, which can be confused with blood during the colonoscopy. You may not be able to eat or drink anything after midnight the night before the exam.
- Take a laxative. Your doctor may suggest taking a laxative, in either pill form or liquid form. You may be instructed to take the laxative the night before your colonoscopy, or you may be asked to use the laxative both the night before and the morning of the procedure.
- Use an enema kit. In some cases, you may need to use an over-the-counter enema kit — either the night before the exam or a few hours before the exam — to empty your colon.
- Adjust your medications. Remind your doctor of your medications at least a week before the exam — especially if you have diabetes, high blood pressure or heart problems, if you take medications or supplements that contain iron, or if you take aspirin or other medications that thin the blood, such as warfarin (Coumadin) or clopidogrel (Plavix). You may need to adjust your dosages or stop taking the medications temporarily.
- Corbett JV. Laboratory Tests and Diagnostic Procedures With Nursing Diagnoses. 7th ed. Upper Saddle River, N.J.: Pearson/Prentice Hall; 2008:745.
- Schilling McCann JA, ed. Diagnostic Tests. Philadelphia, Pa.: Lippincott Williams & Wilkins; 2007.
- Colonoscopy. National Institute of Diabetes and Digestive and Kidney Diseases. http://digestive.niddk.nih.gov/ddiseases/pubs/colonoscopy/index.htm. Accessed April 29, 2011.
- Colorectal cancer screening. Bloomington, Minn.: Institute for Clinical Systems Improvement. http://www.icsi.org/guidelines_and_more/gl_os_prot/preventive_health_maintenance/colorectal_cancer_screening/colorectal_cancer_screening_6.html. Accessed May 2, 2011.
- Levin B, et al. Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: A joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology. Gastroenterology. 2008;134:1570.
- Picco MF (expert opinion). Mayo Clinic, Jacksonville, Fla. May 6, 2011.
- Rex DK, et al. Guidelines for colonoscopy surveillance after cancer resection: A consensus update by the American Cancer Society and U.S. Multi-Society Task Force on Colorectal Cancer. CA: A Cancer Journal for Clinicians. 2006;56:160.