Colonoscopy Prep Instructions

Colonoscopy Prep Instructions

Our office regularly uses one of two similar solutions: Suprep or Clenpiq. They contain medications that, when taken orally, will hold water in the bowel so it does not get absorbed into the body. These solutions are not really drugs since they don’t get absorbed into the bloodstream but remain in the colon. The result is that the clear liquids you drink along with them will act as a kind of “colonic” from above – flushing through the colon and washing it clean. We have also found that the “split prep” technique works much better than taking the whole preparation the evening before the exam. You will receive instructions to take half the solution in the evening and half of it very early in the morning.

The morning of the day of the prep you can have a light breakfast. Don’t eat a lot of bulky fiber, especially seeds – we are always seeing chia, sesame, quinoa, flax seeds, etc., in an otherwise clean colon, and they clog up the scope and hide small polyps, so you should try to cut them out of your diet for 2-3 days before your colonoscopy.

After breakfast, you should have nothing except clear liquids until your exam the next day. Be creative with your clear liquid restriction: anything water-based that light shines through counts as a clear liquid, e.g. jello, chicken broth, popsicles, sorbet, juice without pulp, Gatorade, Miso (without the tofu!). Blended foods do not qualify. Also, no dairy and no protein.

The first prep solution bottle should be drunk sometime after work the evening before your exam. Don’t make any plans to leave your house after you start the process – the first bowel movement will arrive unexpectedly without warning any time from one to about four hours after you finish the liquid. Follow the prep solution with at least 40 oz of clear liquids and keep drinking as much as you can to avoid dehydration. It is easy to get faint and light-headed if you do not drink enough fluids. 

The second bottle is the one that really does the important final preparation. The idea behind the timing of the second bottle is this: For a safe anesthetic, your stomach should have NO clear liquids going into it for three hours (at a minimum) before your procedure. This way it will be empty while you are sedated and there will be no chance of you aspirating while you are asleep.

So, make sure you know the time of your procedure, and make sure you have finished the second bottle of prep AND any extra clear liquids, three hours before that. If you assume it will take about an hour to wake up, drink the second bottle and finish any extra clear liquids, then you should set your alarm for about four hours before the colonoscopy time and start the second half of your preparation right away.

Some patients still prefer to use old fashioned Miralax preparation, or Osmoprep, which is done with pills (a lot of them!). These instructions are given individually but the principle remains the same: half the night before, and half about four hours before the exam. Whatever system you use, this modern way of timing the intake will make for the best chance of an effective cleansing and a good, safe exam.


Miralax & Gatorade Prep

What to Buy To Prepare for a Colonoscopy

Purchase Miralax 238g (8.3 oz) and 4 Dulcolax Laxative Pills (Not stool softeners) at the pharmacy (over the counter). Also (2) 32 oz. Bottles Gatorade (NO RED).


  • * Prepare two doses of the Miralax/Gatorade Mixtures. Divide the entire bottle of Miralax into two 32 ounce bottles of Gatorade.
  • * Have a low residue breakfast BEFORE 10am. (white toast, eggs, yogurt, cream of wheat, smoothies without seeds)
  • * AT 10am begin a “Clear Liquid Diet.” Clear liquids include water, juice without pulp, soda, black coffee, tea, electrolyte drinks, Ensure CLEAR, Boost Breeze, Jello, Broth, Popsicles.
  • * AT 6pm take 2 tablets of Dulcolax and drink the first 32 ounces of Miralax/Gatorade Mix.
  • * Drink the entire 32 ounces within 90 minutes.
  • * Continue drinking clear liquids until bedtime.

On The Day of Your Colonoscopy

  • * Wake up 5 hours before your arrival time to start the second prep dose. 
  • * Immediately take 2 tablets of Ducolax and drink the second dose of Miralax/Gatorade Mix.
  • * Drink the entire 32 ounces within ninety minutes.
  • * You must complete your prep and discontinue clear liquids 2 hours prior to your arrival time.
  • * You should take your regular medications, as prescribed, with sips of water.


To improve the taste try

1. Add ice/Refrigerate mixture

2. Use a straw to drink mixture

If you experience nausea or vomiting, rest for 15 minutes, then try to resume prep.

Use Vaseline or an ointment for diaper rash around the anus before and/or during prep to minimize irritation from passing bowel movements.