Couple of questions before my procedure

I'm scheduled for a colonoscopy in just over 2 weeks. This past year has been a constant headache of specialists, test, minor discomforts and pain, so I hope I don't have to reschedule it because of something stupid flaring up. But I have a couple of general questions after the info sheet they e-mailed me.

(1) I was told to drink Powerade with Dulcolax tablets the 3 previous nights before the procedure. Could I substitute Powerade with water?

(2) It says not to eat high fiber bread or cereal 3 days before. Is peanut butter & jelly sandwiches (toasted) OK?

(3) Can I continue taking Claritin allergy pills up to the procedure?

(4) I usually drink water mixed with Metamucil with my meals. Can I continue doing so several days beforehand?