Has anyone who has colitis have severe constipation that laxatives have no effect. Doctors need to see lining of bowel 1 failed colonoscopy?

[Skye22]

Laxatives for colonoscopy failed. Go back to hospital next week for CT colonography. Now drinking different bowel prep. I have severe bowel dysfunction, (slow transit colon). I'm really anxious as my pain has got much worse and it's like I can feel my colon is inflamed. What happens if these laxatives fail again, what would be the next steps to try to see lining of colon. Many thanks.