Check with your doctor, but I'm pretty sure Imodium is safe to take long term.
This doctor says it's okay: https://www.iffgd.org/lower-gi-disorders/diarrhea/long-term-use-of-loperamide.html
Cholestyramine might work if your diarrhoea is caused by bile acid malabsorption (quite possible if you've had your terminal ileum removed, as that's where bile acids are absorbed).
Dx Crohn's in June 2000. (Yay )
Tried: 5-ASAs, azathioprine, 6MP, Remicade, methotrexate, Humira, diets.
1st surgery 20/2/13 - subtotal colectomy with end ileostomy.
2nd surgery 10/7/15 - ileorectal anastomosis. Stoma reversed and ileum connected to the rectum.
Current status: Chronic flare. Do I have any other kind?
Current meds: 50mg 6MP; Entyvio (started 3/11/16)