Same-Day Colonoscopy Prep: Q&A with Dr. Kastenberg

kastenberg-resizedEvery year more than 14 million Americans have colonoscopies, a procedure that is highly effective in detecting and removing precancerous polyps. While the number is large, it also means that only about half of Americans who should have the test performed are actually getting it.

It’s not easy to convince your loved ones – or even yourself – to get a colonoscopy. It’s not that the procedure itself turns people away; it’s the colon cleansing prep required before your procedure!

For those of you who have experienced the two-day prep, you know all too well of the side effects of chugging that clear, yucky mixture – sleep loss, abdominal pain, bloating, nausea and sometimes vomiting. It’s no fun.

But what if you could take the prep entirely the morning of the procedure? Researchers at Jefferson conducted a randomized study of 116 colonoscopy patients given either a split dosage of colon preparation the night before and morning of their colonoscopy (already an improvement over the old way of doing things) or the colon preparation solely the morning of their procedure.

The study found that both treatments are equally as effective. At Jefferson, our patients have access to both split-dosage prep and now the same-day prep for colonoscopies.

We caught up with the study’s principle investigator David Kastenberg, MD, of Jefferson’s Division of Gastroenterology and Hepatology, to learn more about the same-day colon cleansing preparation. Here are his answers to some common questions.

1. How many hours before the colonoscopy do you start taking the liquid prep, and how much of it?

For the same-day colon prep, you take the first dose 7 hours beforehand and the second dose 4 hours beforehand, one liter at a time.

2. Is the prep the same other than the time doing it, or is a different combination of drugs used?

Yes, the prep is the same as the split-dosage prep. The same drugs are used.

3. When do you start fasting for the same-day prep?

I like to tell my patients that they can eat breakfast up until 10 a.m. on the previous day. Then it’s just liquids up until 2 1/2 hours before the procedure.

4. If it’s equally effective as the split prep, why isn’t it recommended for all patients?

The same-day prep is the new gold standard for colonoscopies, but if you have certain medical conditions – the main medical reason is diabetes – then it’s not recommended. It’s also based on personal preference.

5. Are appointments made at a certain time of day for the same-day prep?

Colonoscopies for same-day prep are scheduled at noon or later. So, if your appointment is at noon, then you would have to start the prep at 5 a.m.

6. Are the side effects reduced or eliminated?

During the study I led, we showed that people got better sleep the night before, that patients were more effectively able to work the day before and that they have less abdominal pain with the same-day prep. The side effects of nausea and vomiting, however, remain the same.

7. If taking the prep liquid so close to the procedure, will this affect getting to the appointment?

This is a common concern of patients. The answer is no, this will not affect you getting to your appointment. The second dose starts working much quicker and has a much shorter duration.

8. Can my doctor still get a clear view of my colon if taking less of the liquid prep?

Absolutely. It works very well and is highly effective.

If you’d like to schedule a colonoscopy at Jefferson, please call 1-800-JEFF-NOW or find a doctor.

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4 Responses to Same-Day Colonoscopy Prep: Q&A with Dr. Kastenberg

  1. alice white April 30, 2013 at 4:43 pm #

    I am really upset to hear that I was not told about other ways to do this. I have never had one before and drinking this sewage water will keep me from ever doing this again. I just want to throw up this stuff is horrible and no one told me about any other options this is terrible doctor work not telling other options.

  2. Norah June 27, 2013 at 12:24 pm #

    Why can’t they simply offer colonic irrigation prior to a colonoscopy? MUCH easier than taking any sort of liquid prep.

    • David Kastenberg June 28, 2013 at 8:59 am #

      All colon cleansing agents that are FDA approved must show the following – efficacy (the entire colon is clean such that small polyps can be detected) and safety (there are no dangerous changes in blood electrolytes, no serious adverse events, no problems with infectious complications that could happen with administration of a cleansing agent). None of these things have been demonstrated for colonic lavage. – David Kastenberg, MD, FACP, AGAF


  1. Colonoscopy Can Prevent Colorectal Cancer | @Jeff - Helping You Keep In Touch with Jefferson University Hospitals - March 5, 2013

    […] Ritchie added that despite what you may have heard about colonoscopy, much has changed in recent years, including the pre-screening preparation patients must undergo. The prep solutions have improved and unlike the process in the past, which required two days’ worth of solutions, Jefferson patients can now undergo same-day preparation. […]

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