@Anna625 its pretty strange that you can have a healthy pouch for 20-30 years and then it starts acting up.
What did your diet look like before?
and did it changes somewhat before your pouchitis started?
The taste of Flagyl was never a problem for me. There was a little metallic taste some hours after taking the pill, but only if I took the full dose. I was taking a small dose of both Cipro & Flagyl for about 3 years till recently.
Right now I started a new biologic therapy with Skyrizi. During a hospital stay due to a Covid infection (my first, the problem was not flu symptoms but diarrhea as usual, associated with weight loss, circulatory problems, kidney failure) in November I was recommended to stop Antibiotics. My GI doc had already suggested to try Skyrizi, so I agreed. For keeping inflammation (chronic pouchitis / ileitis) under control in the meantime, I was put on a prednisone medication. I also add a little budesonide in the evening for local effect.
My first infusion with Skyrizi (Risankizumab) was last week. It is a advanced med compared to Stelara (Ustekinumab) and applied for people with Crohn's (my current diagnosis is "colitis indeterminata", which is ok for me as it says nothing in detail and fits for this kind of post-UC inflammation).
Skyrizi blocks a certain inflammation mediator (IL23, while Stelara was blocking both IL22 and IL23 which is said to be a little counterproductive). The first 3 applications are infusions in 4 week intervals, afterwards you can use an applicator (subcutaneous injection) every 8 weeks. There are usually little side effects. It has already been in use for some years for treating psoriasis, the approval for Crohn's disease was just recently.
I hope that this med will work for me. Over the last 10 years I was already trying Remicade, Entyvio, Stelara, azathioprine, Xelianz and adalimumab. None of them was really helpful, only antibiotics always worked very effective. Yet my liver labs were strongly elevated during the last years when I took antibiotics daily. Right now I'm relieved that they have almost normalized, within some weeks only.