Mesalamine as a Suspected Cause of Drug-Induced Pancreatitis: A Case Report and Review of Diagnostic Considerations.

Acute pancreatitis (AP) is a common cause of gastrointestinal-related hospitalizations in the United States. It is characterized by pancreatic inflammation and necrosis, with diagnosis based on elevated pancreatic enzymes, characteristic imaging, and epigastric pain radiating to the back. While gallstones and alcohol are the predominant etiologies, drug-induced pancreatitis (DIP) accounts for up to 5% of cases and remains a diagnostic challenge. Over 500 medications, including mesalamine, have been implicated. Proposed mechanisms of DIP include pancreatic duct obstruction, toxic metabolite accumulation, hypersensitivity reactions, and localized angioedema. Prompt recognition and withdrawal of the offending agent are critical to prevent complications. We report a 53-year-old female with multiple comorbidities, including chronic kidney disease and type 2 diabetes, who presented with persistent upper abdominal pain, nausea, and vomiting. Imaging revealed an enlarged pancreas with peripancreatic inflammation, consistent with AP, despite normal serum lipase levels. Laboratory workup excluded common etiologies such as gallstones, alcohol use, and hypertriglyceridemia. Given the temporal association, mesalamine was identified as the likely offending agent and discontinued, resulting in symptom resolution. The patient was managed with supportive care and discharged in stable condition. DIP is a rare but important differential in AP, particularly in patients with complex comorbidities and polypharmacy. This case illustrates the diagnostic challenges of DIP and underscores the importance of thorough medication review and early withdrawal of the offending agent to ensure favorable outcomes. Clinician vigilance is essential in recognizing less common causes of pancreatitis, such as mesalamine-induced DIP.