If the stricture is caused by scar tissue rather than inflammation, no medication will make it any better - inflammation can be treated medically, scar tissue can't. It will just slowly get worse over time as more scarring builds up. Based on what you've said, it sounds like time for surgery to me.
For short strictures, strictureplasty or dilation can be an option, but yours sounds too long for that, so it will almost certainly have to be a resection.
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)