I did the Miralax prep last time (I tried Fleets the first time and will never ever take that again). It didn't start working until 9 pm before my c-scope, even though I had taken however much was prescribed. I didn't sleep that night; I was so weak and nauseous when I got to the hospital that they had to hook me up to fluids and nausea meds before the scope.
I didn't find the whole drinking tons of fluids that bad; it was annoying but not completely horrible. I typically don't drink Gatorade, so I used that.
Female, Age 19
9 Asacol, Rowasa, 1000 mg Canasa, Proctofoam, Rifaximin 2/day
Digestive Advantage (Crohn's & Colitis), 1 Florastor, 50 mg 6MP, 1 Primadophilus reuteri, Remicade (4 infusions), 2.4 g Lialda, 1 Forvia, 6 Colazal/day, 2 Anucort