I just had an edoscopy done last week without any IV medication at all. The reason for me not going under was that I have a neuro-muscular disease that has made my breathing pretty bad, so they were very concerned about
reducing my breathing anymore, so I decided to do it completely awake.
They sprayed the back of my throat with a numbing agent, put something in my mouth to hold it
open, then he stuck the camera/tube down my throat. It wasn't pleasant, but it was bearable for me. The procedure took only about
5 minutes, and he even stuck a tube down to stretch my esophagus. If I had a choice in the future, I would stay awake again. They can give you a relaxer too that doesn't put you under, but I chose not to have anything.
I personally think I'm a whimp when it comes to pain, but I think everyone is different when it comes to his tolerance. I've just been through a lot of procedures in the last 3 years, this is middle of the road in terms of discomfort for me.