Penn Medicine GI specialists perform colonoscopies as a routine procedure to evaluate gastrointestinal disorders.

What is a Colonoscopy?

A colonoscopy is an examination of the lining of the rectum and colon (the large intestine) through a flexible tube called a colonoscope. This allows a specially trained doctor to directly view this area and identify, biopsy, or remove any abnormalities such as polyps. Removal of polyps helps to prevent colon cancer.

  • Bowel preparation (cleansing) is needed to perform effective colonoscopy. Any stool that is left in the colon can hide polyps and small cancers and result in the need to repeat the colonoscopy. Therefore, it is critical that you follow the instructions as directed.
  • You will be given sedation for the procedure. For your safety, you must arrange for a responsible adult to escort you home after the procedure (you are not allowed to leave the facility alone).
  • If you are planning to take a bus, cab (taxi) or paratransit home from your procedure, you must have someone with you other than the driver. If you do not have an escort at the time of your procedure, your procedure will be canceled.

What To Expect

Colonoscopy Preparation

Colonoscopy patients will need to take several steps to ensure a successful procedure. Purchase bowel preparation materials at least two days before your test. Your doctor may provide you with a prescription for a laxative to cleanse your bowel. This can be filled at any pharmacy. If you do not receive a prescription from your doctor, your doctor may recommend you purchase the following:

  • One bottle of MiraLAX (238 grams)
  • 4 Dulcolax (Bisacodyl) tablets (5 mgs each tablet)
  • 64 ounces (two 32 ounce bottles) of Gatorade (not red or orange) or Crystal Light Natural Lemonade. If you are a diabetic, you should purchase Crystal Light Natural Lemonade or Pedialyte instead of Gatorade.

Prior to Your Colonoscopy:

  • Two days prior to your test try to eat a low residue diet and follow a clear liquid diet the day before your test (see the section on food and drink).
  • Make arrangements for a responsible adult to bring you home after your procedure.
  • Review your medication list one week prior to your test (see the section on medications). Contact your ordering provider if you have any questions about the medications list below.
  • Bring a list of all your medications (prescription medications, over-the-counter medications and eye drops) along with dosages with you on the day of your colonoscopy procedure.
  • You may bring the medication bottles themselves.
  • Be prepared to list and describe your allergies and reactions to any medications.
  • Be prepared to provide the name, address, phone, and fax number of your family and referring physician.
  • Bring your photo ID.
  • Bring your insurance card(s).
  • Bring referrals, if applicable.

Note: Any out of pocket co-pays, coinsurance, and deductibles are expected on the day of service.


To properly prepare for your procedure, you may also need to make certain changes to your daily medication routine. Some medications will need to be stopped or adjusted before your procedure:

  • Iron Tablets: Stop taking iron supplements seven days prior to your procedure.
  • Diabetic Medication: If you take insulin or diabetes pills, consult with your physician one week prior to your procedure about making any necessary changes in your daily regimen. Some adjustments may be needed. Please inform your physician that you will be on a clear liquid diet the day prior to and the day of the test. It is typically recommended that you do not take your diabetes pills or insulin on the morning of your test. Make sure you check your blood sugars often while taking the prep solution and during the morning of your test.
  • Blood Thinners (Some examples include Coumadin, Plavix, Heparin, Lovenox, Fragmin, Pradaxa, Zorpin, and Xarelto): Check with your prescribing physician one week prior to the procedure to see if it is safe for you to continue taking a blood thinner. Your prescribing physician should give you directions on how to take them before and after your test. Do not stop taking any medications without speaking with your prescribing physician.
  • If you take medications that contain aspirin or other anti-inflammatory drugs (such as Motrin, Advil, Indocin, or Feldene), we recommend that you stop taking them seven days before your procedure. They may increase your risk of bleeding after removal of a polyp or a biopsy during your colonoscopy by interfering with the normal clotting of your blood.
  • Certain medications should be continued prior to your colonoscopy. If you take cardiac (heart) or anti-hypertensive (high blood pressure) pills, take them as you normally do with small sips of water.
  • You can take all other medications the morning of your procedure with a small amount of water. You should take your medication at least three hours before your arrival time.
  • RADNOR PATIENTS ONLY: DO NOT take any diuretic medication (water pill), the day of the procedure. If you are scheduled in the morning, please DO NOT take the following blood pressure medications: Valsartan (Diovan), Losartan (Cozaar), Irbesartan (Avapro), and Candesartan (Atacand).

The Day Before the Test

Follow a clear liquid diet the day before your procedure. Starting when you wake up, do not eat solid food for breakfast, lunch, or dinner. Do not drink milk or alcohol the entire day before. You should drink only clear liquids. Make sure you drink at least 8 oz. of clear liquids every hour while awake. (If you are a diabetic, you will need to drink Crystal Light Natural Lemonade or Pedialyte.)

Clear liquids include the following:

  • Water: tap, spring, sparkling, or seltzer
  • Juice: apple, white grape, or white cranberry
  • Soda: diet or regular, lemon, lime, ginger ale, Sprite, or 7Up
  • Coffee or Tea: No milk, cream, or powered creamer
  • Gelatin: Jell-O (Not red or orange)
  • Sherbet, Popsicles or Water Ice: lemon or lime (Not red or orange)
  • Clear Broth: beef or chicken broth without noodles
  • Gatorade: (Not red or orange)
  • Crystal Light Natural Lemonade
  • Pedialyte

Take four Dulcolax (Biscacodyl) tablets by mouth at 4 pm the day before your procedure. At 5 pm, mix the entire 238 gram bottle of MiraLAX with 64 oz. of Gatorade, Crystal Light Natural Lemonade, or Pedialyte in a large pitcher. Stir and place in refrigerator. (Must be consumed within 24 hours of mixing.)

Beginning at 5 pm the day before your procedure, drink an 8 oz. glass of the MiraLAX solution every 15 minutes:

  • 5 pm - Drink 8 oz. of MiraLAX solution
  • 5:15 pm - Drink 8 oz. of MiraLAX solution
  • 5:30 pm - Drink 8 oz. of MiraLAX solution
  • 5:45 pm - Drink 8 oz. of MiraLAX solution

Important: The remaining 32 oz. of MiraLAX solution will be consumed the day of your test.

Continue to consume clear liquids until bedtime.

The Day of the Test

Drink the remaining 32 oz. of your MiraLAX solution starting six hours prior to your scheduled arrival time:
  • 6 hours before procedure - Drink 8 oz. of MiraLAX solution
  • 5 ¾ hours before procedure (15 minutes later) - Drink 8 oz. of MiraLAX solution
  • 5 ½ hours before procedure (15 minutes later) - Drink 8 oz. of MiraLAX solution
  • 5 hours before procedure (15 minutes later) - Drink 8 oz. of MiraLAX solution

Time Chart Reference Guide for Second Dose of Miralax Prep (PDF)

Important: For your safety, DO NOT take anything by mouth (including chewing gum, mints, etc.) within three hours of your arrival time.

  • Pack lightly and wear loose, comfortable clothing. Leave your money and all other valuables, including jewelry, at home.
  • You can brush your teeth.
  • The test takes about 30 to 60 minutes, but plan to spend 2 to 4 hours at the unit to allow time for your preparation, your test, and your recovery. Every effort will be made to keep your appointment at the scheduled time, but in medicine, unexpected delays and emergencies may occur and your wait time may be prolonged. We give each patient the attention needed for his or her test.
  • Before the test, a nurse will greet you and help you change into a hospital gown.
  • The nurse will place an intravenous (IV) in your arm. You will receive relaxing medicines through the IV during the test.
  • You will be lying on your side for your colonoscopy and the flexible tube will be passed into your rectum to view the lining of the rectum and large intestine (colon). The test takes approximately 30 to 60 minutes to complete.
  • Because you will receive a relaxing medication during your procedure, you must arrange for transportation from the hospital.
  • This procedure is performed very safely in the ambulatory setting. However, if you develop the need for acute care you will be transferred to the nearest hospital.

After the Test

  • After the colonoscopy, you will go to a recovery area where a nurse will watch you until most of the effects of the relaxing medicine have worn off.
  • You may have some cramping or bloating because gas is placed into your intestine during the test. This should go away after several hours.
  • The nurse will give you information about how to take care of yourself at home.
  • A copy of your test report will be sent to your referring doctor.
  • We will provide a phone number for you to call for results of biopsies or other tissue sampling performed during your test.
  • You should not: Drive a car, operate any machinery or power tools; drink any alcoholic beverages, or make any important decisions until the following day.

If you would like to speak to a nurse regarding your procedure or preparation, or if you need to reschedule your procedure, please call the appropriate number:

  • Perelman Center for Advanced Medicine
    • Procedure Questions: 215-662-2122
    • To Reschedule: 215-349-8222
  • Penn Presbyterian Medical Center
    • All Questions: 215-662-8900
  • Pennsylvania Hospital
    • All Questions: 215-829-3561
  • Penn Medicine at Radnor
    • All Questions: 610-902-1500

These instructions apply to patients scheduled for procedures at Penn Gastroenterology. However, your doctor may give you different instructions or procedures. If you have questions about your procedure, contact your physician at Penn Gastroenterology.

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