When I had a barium enema [the highlight of my life to date!!], the instruction sheet said not to take to stuff till 4 p.m. Fortunately, I took it at 10 a.m. and was able to get some sleep that night as I was pretty much cleaned out by then. Might want to keep that in mind depending on your situation--I'm blessed with the Big 'C' so it takes longer to get my system moving.
The waiting and worrying is far worse than the procedure. All I remember is glacing up at the monitor and seeing what looked like a pink wormhole. Next thing I knew, I was in recovery coming to.