Oxycodone isn't helping your UC, it's just depressing your colon (slowing down to nothing) so it appears you have fewer symptoms. Not a good way to treat UC and can potentially cause toxic megacolon if your colon stops moving.
I don't know what country you are from but biologics, both Humira and Remicade usually get tried before surgery in the US. Ask your doctor why he isn't suggesting them.
I did not want to go to biologics (failed all the other lower level meds) so kept at diet modification (no prednisone) until slowly getting better.
Surgery is not the end of the world, I'm glad it's there if I need it someday. Get a second opinion from another GI (not a surgeon) before scheduling surgery. Get copies of all your blood tests, meds taken in the past, colonoscopy results including biopsies and take them with you or you won't get any worthwhile answers or #2 GI will want to schedule another c-scope. If you've had one in the last 6 months you shouldn't need another unless things have gotten very bad since then.
Oxycodone is one of the best drugs I have been prescribed for my UC. It does indeed slow down the GI allowing me to eat and absorb the nutrients of my food.
Up until 2009 hospital stay I never had used any opiates or narcotics; the nurse strongly encourage pain medication saying my extreme pain was additional stress which was not allowing me rest and ability to heal as well.
I take 40 mg oxycodone per day and in 2010 was at 60mg/day and in the hospital I was severely malnourished ; the strong IV pain meds in the hospital allowed me to eat and recover while the Imuran, mesalamines and solumedrol kicked in and healed the colon. Remicade was then also added after I was out of the hospital. It was that pain medication which allowed me colon rest and, wow, did I all of the sudden have an urge to eat without dreading bloody bm's.
For a headache or other aches and pains oxy doesn't help but I'd be non-functional without it. Remicade, Imuran Apriso and Oxycodone are all legitimate medications for UC. I wish I had known about
oxycodone back in the 1980's. All that pain and diarrhea I went through.
As for being 'pre-approved' for a drug from BCBS; I've been through that myself. Don't let them send you from one agent to the next. I didn't have pre-approval once and had not gone to my GI in over a year so they denied my Remicade. You need to try Remicade IMO. My solution was I faxed BCBS medical notes from another doctor. They don't explain things well. If it's like my insurance you basically have 1 year from each medicine approval and you're required to at least see you doctor once a year (get that cleared up for the future).
Hope it turns better.
I would call and hound them and not let up on them paying. Sure wish you could recall the drug.
You might just required more steriods. I was on 80 mg to prednisone then when hospitalized I was put on 60 mg solumedrol (IV) plus IV pain meds and a lot of mesalamine plus 150mg imuran and Remicade...just thinking more steriods (IV) is a shot until that Imuran kicks in.