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Things to Know Before Your Colonoscopy


Information for Your Colonoscopy Preparation

There have been many systems devised to clean out the colon and prepare it for both surgery and colonoscopy, and none of them are delicious or fun! But there is no doubt that the modern cleansing solutions we use are much easier than the nasty liquids patients had to drink in the past. There will never come a day when colonoscopy preparation is pleasant, but compared with many things that doctors do to patients it is a small inconvenience, so please don’t complain to the nurses as it will fall on deaf ears – we have all had to do it too!

Our current system 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, therefore, 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. Since we have adopted the split prep, the colons we have examined have been much cleaner and we have been finding and removing more polyps as a result.

These new preparation systems are not cheap, but you only need to spend the money every five to ten years, so they are worth it! You should receive detailed instructions and a timeline for your preparation from Zettie, our scheduler, but in case you lose them, the general plan is this:

The morning before 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 two 16 ounce glasses 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. 

Eventually, after a good clean-out, you should be able to go to bed and get some sleep BUT – this is not enough for a totally clean colon, and that 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 Instruction Brochure


Mark Bazalgette, M.D.
165 Rowland Way, Suite 200
Novato, CA 94945
Phone: 415-364-8918
Fax: 415-895-5870

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