Fear not. This is a good thing.
I had, post my diagnosis with ulcerative colitis somewhere ca. 1987-88, something like 15 colonoscopies, and so I speak with a certain level of experience on the matter.
In the early days, before the advent of industrial strength bowel cleansing agents, you had to start the “prep” a couple of days prior with nothing but broth and Jell-O and clear liquids. Then, the night before, you had to have a bottle, maybe two, of magnesium citrate. Then in the morning, you had to use a Fleet enema.
Good prep is important. If you screw it up, then you have to start all over again.
The thing to keep in mind is that the prep is the hardest part. The first time I ever had one of those four-liter jugs of purgative, I had heard from a friend that it was horrible. I mixed the stuff up and sat down to drink it. The first cup wasn’t so bad. The second cup was a little less so, and by the 20th or so, I had developed a deep loathing for the stuff.
It pretty much works as advertised, which is to say that you finish it up by about 7 p.m., you’re purged by 11 p.m. It’s pretty much entirely unpleasant, but likely way less unpleasant than dying of cancer.
It wasn’t until about my second-to-last colonoscopy that I discovered a way to make the prep a little less unpleasant. I asked my doctor, “Is gin a clear liquid?” He laughed and said, “I suppose so.” And so when I did my prep, I’d have a cup of the purgative, and then a gin chaser. Didn’t make the Go-Lytely taste any better, but it sure did make things seem a little bit less dreary, and perhaps even humorous.
And if you’re a coffee drinker, as I am, you’re going to have a massive headache by the time you have your colonoscopy, but I’d say don’t worry about a hangover. The whole thing about those Go-Lytely-type purgatives is that they’re designed to clean you out without robbing you of electrolytes. I have no idea whether the gin screws with that. But I’m not suggesting downing the whole bottle.
This is not intended as medical advice. Your own doctor may not see gin the way mine did. Anyway, be happy you have a colon, and not a diseased one. Before it was removed, mine looked, on the screen during flexible sigmoidoscopies and colonoscopies like a pizza with the cheese torn off. Which tends to make the whole thing, from purging to the actual “procedure” a lot more painful. If you have a healthy colon, it should be painful at all.
One more thing, though. If they offer you the chance to be out for the whole thing, take it.
And one other more thing: they use air to inflate your colon when they scope it, so afterward, you will be passing that air right back out. No big deal. It can even be kind of funny.