I had no problem getting my colonoscopy without drugs, and I recommend considering this route. It's very cool to see what's going on—how often do you get to see your appendix? Discomfort was minimal; I get more pain from my abdominal workout at the gym. (Although I suspect my doctor was unusually good.) For the most part, it was kind of like watching a procedure on TV, with occasional reminders that I was the subject: "You're watching in Cramp-O-Vision!" It was nice to have zero recovery time and drive home.