Bowel Prep

Why Bowel Prep is Necessary

In order for the results of a colonoscopy or other endoscopic procedure to be effective, you will need to practice traditional bowel prep during the 1 or 2 days leading up to the appointment. Because the doctor is primarily examining the inside of the patient’s bowel for growths or other abnormalities, it is important that fecal matter located in the large intestine does not get in the way, or obstruct, the doctor’s view. Any residual fecal matter can also look like a growth and produce a misleading diagnosis or result in missing underlying pathology.

An enema can usually be used for a final cleansing right before the procedure starts. However, during the days leading up to your colonoscopy, you’ll need to completely empty your bowel by ingesting medication and laxatives and strictly avoiding solid foods for at least 24 hours before the procedure.

Bowel Prep Medication

Two types of medication will be necessary during bowel prep, both of which are designed to encourage frequent bowel movements. The first is a drinkable laxative that loosens your stool and causes diarrhea while the second medication is meant to reduce nausea and assist your body in processing the laxative.

Unfortunately, patients usually find the necessary process of bowel preparation the worst part of the entire colonoscopy procedure. Many patients opt to stay home from work so that way they can use the toilet freely. Bowel prep can cause discomfort, fatigue and diarrhea. The medications required during bowel prep usually taste bad and can result in vomiting. In contrast, the use of sedation during the actual colonoscopy procedure usually makes the hour or so that you’re in the doctor’s office a simple, easy appointment. The majority of patients do not even remember their colonoscopy procedure after it has been completed.

Step-by-Step Bowel Prep

You may want to eat a light meal on the morning before your procedure, as for the rest of the day you’ll only be able to consume clear liquids such as black tea, chicken broth and clear fruit juices. Some dissolvable hard candies will also be permitted, unless it contained food coloring (especially red or green) that might stain the lining of the colon.

At a specified time, you’ll need to take a prescription pill to prepare your body for the drinkable laxative. When the time comes to start drinking the medication, you should be less likely to vomit or feel sick. The drinkable laxative will be given to you is a large, gallon-sized container. Sometimes it takes patients more than 3 hours to drink the entire solution. Most patients complain that it tastes bad, despite attempts from pharmaceutical companies to flavor the mediation. If patients have issues or feel like they cannot keep the medication down, they can call their medical nurse or doctor for instructions.  Some patients find that mixing the solution with Crystal Light or Gatorade helps to improve the flavor and make the solution more palatable. 

You’ll take another pill once you finish the laxative. Diarrhea will usually start shortly after the drinkable solution in completely ingested and will last almost 2 hours. Depending on how fast you can drink the medication, your experience may vary. Although the prior is the most commonly used bowel preparation approach, some practitioners may have alternative methods – you should discuss the type of prep with your specialist prior to the procedure to find out which prep will be best for you. Contact one of our colonoscopy specialists if you have questions or need help with bowel prep.

Reviewed 12/12/2011 by David M. Nolan, M.D.
Diplomate of the American Board of Internal Medicine, 2011
Currently a Fellow of Gastroenterology, at UCI 2011-2014