You had a side-effect (vomiting) after oral administration of Dormicum and fenatinyl and as a result were listed as being allergic to both medicines. How silly.
If you want to find out if Dormicum makes you vomit, take a tablet at bedtime and see how it affects you.
Separately, on another day, take 1,000 mg (1 g) paracetamol, not fenatinyl or another opioid, and see how this affects you.
If you have no particularly unpleasant side-effects with both medicines, ask for these two to be given prior to your next colonoscopy. For one of my many ESWL (extra-corporeal sound wave lithotripsy) procedures for the fragmentation of kidney stones, an anaethiologist gave me this combination and I slept through the whole procedure and woke up without any ill effects.