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Having a colonoscopy at the U-M Health System
This guide is for patients who are going to have a colonoscopy. It answers some of the most commonly asked questions. If you still have questions after reading this guide, please ask your doctor or nurse for more information.

What is a colonoscopy?
A colonoscopy is an examination of the lining of the colon with a lighted, flexible tube about the thickness of your finger. The doctor will insert the tube through your rectum and up through your colon, checking for abnormalities. Often during the colonoscopy, your doctor may perform other minor procedures such as a polyp removal. In addition, if necessary, a small piece of tissue (a biopsy) can be taken for examination in the lab. Please note that biopsies are taken for many reasons and do not necessarily imply cancer.

General information

Here are the names of some of the common anti-platelets drugs:

  • ReoPro (abciximab)
  • Aggrenox (aspirin plus dipryridamole)
  • Plavix (clopidogrel)
  • Persantine (dipyridamole)
  • Integrillin (eptifibatide)
  • Ticlid (ticlopidine)
  • Aggrastat (terofiban)

Preparing for the test

One week (7 days) before your colonoscopy:

-Make arrangements for a responsible adult to accompany you to and from your colonoscopy appointment.

-Do not take iron or herbal supplements for 1 week prior to your procedure.

-Contact the health care provider that ordered your test if you are currently taking blood thinners.

Two days before your colonoscopy:

-Begin your 2-day bowel prep two (2) nights before your procedure if that is the prep that you have been given.

-All of the preparations are “split dose” which means that you take ½ the preparation the evening before the procedure and ½ the preparation the morning of the procedure.

-If you are unsure whether or not to continue taking the medications you are taking prior to this procedure, please ask your nurse or doctor.

The day before your colonsocopy:

-Begin your bowel prep (if you were given the 2 day prep you should start 2 days before the procedure).

-You may eat a normal breakfast. Do not eat solid food after 12 noon.

-Drink only clear liquids or gatorade for lunch and dinner. Do not drink red, orange, or purple liquids, including Jell-O.

Acceptable clear liquids include:

  • Water
  • Apple juice
  • White grape juice
  • Black coffee
  • Tea
  • Lemon or lime Jell-O
  • Lemon or lime Kool-Aid
  • Soda pops, including colas, 7-Up, Sprite, or Fresca
  • Gatorade

You should have at least 1 to 2 quarts of fluid at midday, another 1 to 2 quarts of fluid in the evening, and again 1 hour before bedtime.

You should start your first laxative dose between 12 p.m. and 6:00 p.m. the night before the procedure to allow the effects of the prep to be completed by bedtime. See your prep sheet for specific directions.

Prep Links

The day of the colonoscopy

1. Take the 2nd half of your bowel prep starting 4 hours before you need to leave for your appointment.

2. You should take your usual morning medications other than those noted earlier. This is especially important for blood pressure and heart medications. You may take pain medication with a few sips of water up to 4 hours before the test. Stop drinking all fluids 2 hours before the test.

3. Please bring all of the following when you come for your colonoscopy:

  1. A list of all medications you are taking
  2. A list of any allergies you have
  3. Health insurance cards
  4. A RESPONSIBLE ADULT TO ACCOMPANY YOU from the endoscopy unit after your procedure.  YOU WILL NOT BE DISCHARGED unless that person is there to escort you from the endoscopy unit.

4. Please leave jewelry at home.

5. Small children will be more comfortable at home.

6. If you have diabetes and take oral diabetes medications (pills): Do not take the medication the morning of your test. Bring your diabetes medication with you.

7. If you have diabetes and take insulin, on the morning of your test: Take ½ of your usual dose of long-acting insulin before the test. Long-acting insulins include NPH, Humulin N, Humulin 70/30, Humalog Mix 75/25, Lantus, and Levemir. If you take Humulin R 500 insulin, take only ½ of your usual dose. Take no short-acting insulin the morning of the test. Short-acting insulins include Regular, Humulin R, Novolin R. Take the other ½ of your long-acting and any regularly scheduled dose of short-acting insulin right after the test. Be sure to eat your usual meal at that time.

Please refer to the handout Instructions for Patients with Diabetes Having Outpatient Procedures, or look at this web site Here is the link to click on: Instructions for Patients with Diabetes Having Outpatient Procedures/Tests.

The procedure
The colonoscopy will be performed in a room especially designed for endoscopy by a doctor specially trained in gastrointestinal procedures. The doctor who ordered your procedure will make decisions regarding your plan of care.

In the waiting room or preparation area you will be asked questions about your health history, current medicines, and allergies. You will also be asked to sign a consent form before the procedure can begin.

After you change into a hospital gown, a nurse will start an intravenous (IV) line that will be used to give you medications to make you more comfortable during the colonoscopy. Equipment that will help the nurse and doctor monitor your heartbeat and breathing will be connected to you.

You will be asked to lie on your left side. You will then be sedated before the doctor passes the lubricated tube into your rectum and colon. As the tube passes through the curves of your colon, you may feel pressure or discomfort, but you will receive medication throughout the procedure to keep you comfortable. The doctor will put air into your colon in order to see the lining, and you may have some bloating or abdominal discomfort from the air. You may feel as though you have to have a bowel movement. Pass the air if you feel the need. The doctor will remove as much air as possible after the procedure. 

If biopsy and/or polyp removal is necessary, you should experience no pain.

After your procedure you will be taken to the recovery area. One family member may join you there. When you are ready to go home the nurse will discuss instructions and answer your questions. You will be given a summary of findings from your colonoscopy. You may not drive yourself home. A responsible adult must be with you when you are discharged from the recovery area.

Be sure to bring a responsible adult, 18 years of age or older, who is a licensed driver with you. Your driver will need to be available in the endoscopy suite before your procedure can begin. You will not be discharged to public transportation or taxicabs unless you have a responsible adult to accompany you.

Post-colonoscopy instructions

U-M Health System Related Sites:
Department of Internal Medicine Division of Gastroenterology
Directions to the Medical Procedures Unit
Instructions for Patients with Diabetes Having Outpatient Tests (on insulin)
Instructions for Patients with Diabetes Having Outpatient Tests (no insulin)

Other Related Web Sites:
NIDDK - Diagnostic Tests - Colonoscopy

Your Digestive System and How it Works

Screening for Colorectal Cancer - see the colonoscopy educational video produced by the American Society for Gastrointestinal Endoscopy

Information provided by UMHS Medical Procedures Unit MPU/MPC staff, August 2014.