You'll have to elaborate on the liquid.  I had my first colonoscopy
last summer, and was prepped with phosphosoda.  I was to have nothing
but clear fluids from midnight before the day before; then 1 1/2 oz
phosphosoda night before, then another 1 1/2 oz. 3 or 4 hours before the
procedure.  I just had some good reading material for the bathroom.  Not
too bad, had general anesthetic for the procedure, and got off the table
maybe 30 minutes after they put the IV in my arm.
    My brother had his first colonoscopy in 1992, and had this Golitely
stuff--maybe 8 oz. every 30 minutes for several hours, and it was
brutal.  Definitely avoid that if your gastroenterologist allows you to.
    The procedure is really no big deal.  My brother was awake, and he said
it was only mildly painful.  I had the general because I'm a sissy.
    Only mistake I made is not taking it easy enough after the procedure.
Needless to say you're pretty dehydrated, and though I'd taken the day
off from work, I did too many  errands running around, it was pretty
warm, and I started to feel a little sick and lightheaded later.
    Yeah, that was pretty stoopid!

Good luck,
Steve

I did the Fleet prep (2 relatively small volume phosphate doses)
spaced 10 hours.  The stuff is unpleasant, but pa-in-law tells me
his gallon of polyethylene glycol solution was gross and unending.

I'd heard tell of dehydration after-effects so I intentionally drank
extra during the 'clear liquids as desired' period.  This must have
averted the problem.

The prep was the worst of it.

Ed