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Side effects of Mesalazine

Hi, I have been living with Ulcerative Colitis for the past 10 years and was swapped to Mesalazine 3 years ago. In the past 13 months I have experienced visible Hematuria with pain in my lower abdomen. I have had all the investigations done from a urology standpoint with no clear answers.

However, In the last 3 days I have had left flank pain with 8/10 pain which comes and goes. The ED Doctor seems to think I have Interstitial Nephritis which is one of the side affects of taking Mesalazine (which I was unaware of)

Has anyone with UC taking Mesalazine experienced the same symptoms?

  1. Hi . Have you seen your gastroenterologist about the side pain? I ask because this is not an uncommon for UC to be on the left side and have left side pain. I do notice that back pain is listed as a potential symptom with interstitial nephritis, but I have not seen side pain mentioned (see: https://www.kidneyfund.org/all-about-kidneys/other-kidney-diseases/interstitial-nephritis). That said, my search was by no means exhaustive and I am not a medical professional. Also, blood in urine definitely is a symptom. My point is that the left side pain could be connected to your UC and separate from the blood in the urine. It is important to look at all possibilities. Is it possible to get your specialists to speak with each other and collaborate on your case. Best, Richard (Team Member)

    1. Hi,


      No I have had a colonoscopy during the past year I have had the hematuria and there was no activity of my UC during this time and no flare ups either. And from my recent past flare ups this is very different. It’s definitely my left kidney. The interstitial nephritis is caused by only a couple of things and one being medication and Mesalazine is the only medication I take which is for my UC. Thanks for reaching out though.

      1. I hope that you can get some answers to what's going on with your kidney! Please, if you're comfortable, let us know what you find out. And hopefully, anyone here with similar experience, can share with you! -- Warmly, Christine (Team Member)

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