Drug-Induced Pancreatitis Caused by Mesalazine in an Adolescent Man With Ulcerative Colitis: A Case Report.

Drugs are a rare cause of acute pancreatitis. Mesalazine, a medication used to treat inflammatory bowel disease (IBD), has been reported to cause drug-induced pancreatitis. Here, we report a case strongly suggestive of mesalazine-induced pancreatitis. A 20-year-old man presented with left upper abdominal pain after eating. He was diagnosed with acute pancreatitis based on clinical symptoms, elevated amylase levels, and findings from contrast-enhanced computed tomography. Notably, he had been diagnosed with ulcerative colitis (UC) and had started mesalazine therapy six months earlier. Mesalazine was strongly suspected as the causative agent and was subsequently discontinued. Other potential causes of pancreatitis, such as alcohol use and gallstones, were ruled out. The patient's condition steadily improved after discontinuing mesalazine, along with general supportive treatment for pancreatitis. No recurrence has been observed over several years since discontinuation. Although re-administration has not been attempted, the clinical course strongly supports mesalazine as the likely cause. When evaluating pancreatitis in patients receiving mesalazine, drug-induced pancreatitis should be considered a potential etiology.