Wow. Most people with raging irritable bowel syndrome wouldn't dream of taking laxatives. When there is a flare (a time where the condition is particularly bothersome and not in remission), constipation is not a problem. Needing to go to the bathroom frequently is the problem.
Doctors will actually suggest anti diarrhea medicine if someone is traveling or something that makes almost constant bathroom breaks a real inconvenience. But laxatives? I don't know that people with a spastic colon deal with those much.