Not really.
It's an IV with some kind of mild trank in it. I fell asleep for my first one, but was awake for this one. Don't know if that was just me, or a different formula. You have to have someone drive you home, but I walked out of the office with no problems or noticable lack of clarity. For my first one, they kept me on liquid diet for a day or so because they'd clipped some polyps, but for this one, they said no such precautions were really necessary.
Worst aftereffect was a sore arse from the marathon poop session.