On Monday I had my 3rd colonoscopy. The cleansing stuff is much better than it was 10 years ago. I had two 6 OZ bottles of Surprep. You take one bottle and mix it with 16oz of water and drink it all, followed by two more 16oz bottles of water over the next two hours. Then you repeat this a few hours before your procedure. It really wasn't too bad and much better than dying of cancer.
Moviprep and Suprep have a long list of contraindications and side effects and patients not infrequently vomit them up and have to cancel the procedure. One sued after becoming dehydrated.