Sitagliptin-induced Pancreatitis: A case report and plausible mechanism

Drugs are rare cause of acute pancreatitis (AP) with an estimate incidence of 0.1-2%. We present an 63-year-man 1 week history of severe and progressive epigastric pain that radiates to the back and is worse on lying down, who was found to have lipase of more than 813 IU/L. The patient denied current alcohol use. Abdominal ultrasound and abdominal computed tomography scan did not show gallstones or biliary duct abnormalities. For his type-2 diabetes mellitus, he was taking Gliclazide and Metformin for years and Sitagliptin was the only drug added 6 months ago. He was managed conservatively with intravenous fluids, pain medications, and control of diabetes with insulin.  Within 3 days, he improved dramatically and was discharged on diabetic diet and Gliclazide 120 mg daily with Lantos 10 units at night.  He was instructed to avoid oral hypoglycemia agents from the dipeptidyl-peptidase IV inhibitors (DPP-4i) group.  Three weeks later, repeat computed tomography scan of the abdomen showed normal pancreas.  On follow up; and up to 1 year, he did not have subsequent AP.  The most plausible mechanism of such late-development of rare drug-induced AP is late-encounter with triggering factor/s for Sitagliptin in genetically-predisposed individuals.    Keywords: CT scan, diabetes mellitus, DPP-4i, metformin, pancreatitis, Sitagliptin.