Post-care is a few day's worth of entry-level painkillers unless the patient gets a dry socket. We use acetaminophen for post-treatment rather than paracetamol, since it's better (never understood the British obsession with that stuff, it's nasty business).
Anywhere else I would walk away from a terrible joke like that, but this is HN. I'm joking.
It's also a rare joke where explaining it won't reduce the effect: by the time a Brit hits the end of the offending sentence, it's too late.
It varies by hospital trust, there is no uniform guideline.
My local NHS hospital sedates for colonoscopy as a matter of course (using fentanyl). But as you say, some don’t, and others ask the patient.
I've had like a dozen of colonoscopies (have to be checked every year cause of risk factors), and they were never really painful.
Nitrous oxide is a fairly strong anagelsic (pain medication) but a very weak sedative. That's exactly why it's often used for minor routine procedures where keeping the patient awake and reasonably alert is more valuable than keeping the patient fully sedated.