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HF 7058

Getting Ready for Your Colonoscopy- Two-Day Prep Using PEG Solution Split -Dose and Magnesium Citrate

Read this entire document at least 1 week before your test. For a printable version of your bowel prep instructions and checklist click on download & print. Let’s review how to get ready for your colonoscopy using a 2-day prep with PEG solution split-dose and magnesium citrate.

1 Week Before Test

Arrange Transportation

Due to the sedation medicines, you must have a responsible adult drive you home. It is recommended that you are observed for at least 6 hours after discharge.

Health Changes

Please tell us about any major health changes, illnesses, or recent hospital stays you have had since you scheduled your test.

If at any time you have symptoms of illness (cough, stuffy nose, sore throat, fever, body aches, chills), please call the procedure center to reschedule your test. You should not have this test while ill.

Iron, Multivitamins with Iron and Fish Oil

Stop taking these 5 days before your test. (You do not need to contact your doctor first).

Blood Thinners and Diabetes Medicines

You must call the doctor who prescribes this medicine to see if you need to stop or adjust your medicine before your test. Your doctor will tell you how to safely do this.

The UW Digestive Health Center suggests talking to your doctor using the table below. That doctor should give you the final advice on stopping these medicines.

Ask your doctor about your bleeding risk with this test. If your doctor feels your bleeding risk is low, they will likely have you follow the schedule below to stop your blood thinning medicines. If your doctor feels your bleeding risk is high, they may have you follow a different timeline.

The list below has common blood thinning medicines. It does not include all blood thinning medicines.

DHC Med List

If your doctor tells you not to stop your medicine, please call the Digestive Health Center at 608-890-5010, as this may affect your procedure.


You may need extra prep if you are often constipated or if you have had problems prepping before. Please call to talk about this in more detail.

3 Days Before Test

Low Fiber Diet

  • Stop the following foods and medicines. These foods may slow your digestion, and your colon may not be clean enough for your test:

  • Corn, popcorn, seeds or nuts.
    Uncooked vegetables, beans and
    lentils, potato skins.

  • Fruits with skins or seeds.

  • Whole grain breads, granola or high fiber cereals.

  • Fiber supplements (like Metamucil®, Citrucel®, or Benefiber®).

  • Anti-diarrhea medicines (like Kaopectate®, Lomotil®, Pepto- Bismol® and Imodium® or

Bowel Prep Tip: For a list of safe foods visit:

Pick up Bowel Prep

Your bowel prep will be ordered about two weeks before your test. Three days before your test:

  1. Call the pharmacy to tell them you will be picking up your bowel prep.

  2. Pick up your bowel prep. Do not mix the prep until the day before the test.

  3. Also pick up the 10 oz. bottle of magnesium citrate, this is bought over the counter.

  4. Buy soft toilet paper.

2 Days Before Test


You can eat and drink like normal until 12 pm, noon.
Begin clear liquid diet at 12pm, noon. Be sure to drink at least 8 glasses of clear “see-through” liquids.

Clear liquids include:

  • Water, clear sports drinks like Gatorade®

  • Broth

  • Black coffee, tea, soda

  • Apple juice

  • Jell-O®

  • No creamers, milks or other dairy products

  • No red or purple liquids or Jell-O

  • No solid food

  • No liquids with ‘pulp’


Take your daily medicine, except those you were told to stop. Take your medicines at least one hour before or one hour after drinking your prep.

Begin Bowel Prep

Between 3 pm-5 pm, drink a full bottle of magnesium citrate. This may give you loose stools and mild cramping. It could take from 30 minutes to 8 hours to start working.

1 Day Before Test

Mix the Prep

  • Mix prep as instructed on the jug and place in the fridge.

Bowel Prep Tip : Take bowel prep out of the fridge at least 2 hours before drinking.


Continue clear liquid diet. No solid food.


Take your daily medicine, except those you were told to stop. Take your medicines at least one hour before or one hour after drinking your prep.

Bowel Prep

  • Start drinking your prep at the time listed on your Prep Checklist.

  • Follow the directions on the checklist. Do not follow the directions on the jug. Once you have finished the amount of prep listed on your checklist based on arrival time, put the rest of the prep in the fridge.

  • Stay near a bathroom. You will have loose, then liquid stools. This is normal.

Bowel Prep Tip: Add yellow Crystal Light® lemonade to each glass improve taste.


You may have cramping, bloating and/or nausea. If you have a lot of nausea or vomiting, slow down or stop for 30 minutes, then start again.

Test Day


  • No food

  • Stay on only clear liquids (no red or purple)

  • Stop drinking everything, even water, 4 hours before you arrive.


If you need to take medicine during the 4 hours before your arrival, drink no more than 1/2 cup of water (4 ounces). Follow your provider’s directions for your diabetes or blood thinning medicines.

Bowel Prep

  • Start drinking the rest of the prep 6 hours before you arrive for your test. This may be in the middle of the night.

  • Drink 1 cup (8oz) every 10-20 minutes.

As you finish the prep, your stools should be watery clear or yellow, with no solids (flecks of stool are OK). If you are still passing solid or brown stools, please call the procedure center.

What to Bring

  • CPAP or BiPAP and any inhalers that you use.

  • Eyeglass or contact lens case, denture cup.

  • Ostomy supplies.

  • Wear comfortable clothing.

  • Phone number for your driver.

Do not bring:

  • Jewelry

  • Money

  • Other valuables

Before the Test

  • When you arrive, you can choose if your driver waits in the waiting room or in your private room where they will hear private health information.

  • The doctor will talk with you, answer questions, and ask you to sign a consent form.

  • A nurse will review your health history, take your vital signs and attach a heart monitor.

  • A nurse will place an IV and give you medicines to help you relax and keep you comfortable.

  • Your visit will take about 2-3 hours.

After the Test

  • Your doctor will review the results and give you a report. We strongly suggest that you have your driver in the room with you to hear the results.

  • You may feel tired when you leave.

  • Spend the day resting at home. You cannot drive or return to work. You can return to your normal routine the next day.

  • It may take up to a week for your bowel habits to return to your normal.

  • If you stopped blood thinning medicine before your test, ask when it can be restarted.


If you have biopsies taken or polyps removed, you can expect to get lab results 1-2 weeks later. Your results will be sent to your MyChart account. If you don’t have a MyChart account, someone will call you with results or results will be mailed to you.

Tip: To learn more about colon polyps visit:

When to Call

  • If you are still passing solid stools or your bowels have not started to empty by the morning of your test.

  • You have severe cramps.

  • You feel dizzy or lightheaded.

  • You have constant pain, rectal bleeding and/or a fever.

Who to Call

Patient Resources

(If you need help finding a ride to and from your test)

Digestive Health Center

(608) 890-5010

UW Hospital GI Procedure Clinic

(608) 263-8094