Hi,yes I cannot take Pentasa anymore,after 18 months I developed serious Liver problems and developed Hepatitus (drug induced Hepatitus),I was mortified.
The Gastro said after bloods done,it was the Pentasa,funny tho for quite a few months,I was waking up in the morning with blood on my pillow,it worried me a little then,I thought my stomach was bleeding,which can happen with aspirin based drugs,also had the problem afew years ago with salazapyrin which is related to Pentasa,another sulfate drug,and it also affected my liver.
So now no 5ASA drugs for me anymore,I am on azathioprine 100mg and not too bad at all with them,
Good luck,hope they can sort you out soon