@sascha2 - I don't and never have taken this medication, but we have members who do. There may be someone with personal experience around in a while, as the forum gets busier for the evening.
One thing I would say though is that regarding your specific query, relating to your colitis; I think that might best be addressed by a conversation with your Doctor who will have a clear understanding of your personal medical history and conditions.
Do your Doctor do telephone consultations? My GP does those, and it's considerably easier to speak to a GP at my surgery than it is to have a face-to-face consultation. Clearly a telephone consultation doesn't work when you need to be examined, but for just a conversation I find them ideal.
Good luck with it all.