Posted 2/1/2011 6:38 AM (GMT 0)
See a doctor!
Asacol is eliminated through the kidneys and one of the rare but serious side effects is nephritis or nephrotic syndrome: http://en.wikipedia.org/wiki/Mesalazine.
If your urine is unusually dark, get your bloodwork done and your urine checked, just to be safe.
I am not trying to worry you. I am not a doctor and I have no details on your other symptoms, but I'd have it looked at. Hopefully you don't have to pay out of pocket for tests...
j.