I was lucky the Dr. I had gave me a mild sedative with mine so I was asleep for the entire procedure.

Like you Janie, I had a Colonoscopy a few years ago and had to take the drink the night before. I does act pretty quickly and especially towards the end of the evening. I was fine the next morning, no sign of running to the loo by then.
It really is worth sticking with it, as when I had mine done the Doctor said it made things much easier for them and me as my bowel was nice and clean. I was even able to watch the procedure on screen. Mind you although it wasn't the pleasantest thing I've gone through, it certainly wasn't the worse.

I had one done a few years ago. I was done with the diarriah the next morning. But while you are drinking the stuff they have you take make sure the restroom is free, you"ll go alot.