I had j-pouch surgery but was taken off 6-mp about a month prior to my surgery as I recall. I don't know if it was removed due to the risk or because the drug was ineffective in my case so why bother taking it? It's probably best to check with both your surgeon and your GI.
dx proctitis in 1987
dx UC in 1991, was stable until 1998
1998 started prednisone, asacol, pentasa, nortriptylene, ativan, 6MP, rowasa enemas and suppositories, hydrocortisone enemas, tried the SCD diet, being a vegetarian, omega 3s, flax, pranic healing, yoga, acupuncture, probiotics
2000 lost all my B-12 stores and became anemic
2001 opted for j-pouch surgery- now living life med-free