New-onset diabetes mellitus after transplant is a well-recognized complication of tacrolimus immunosuppression and commonly occurs as a form of type 2 diabetes mellitus. However, tacrolimus-associated acute pancreatitis causing diabetic ketoacidosis has not been reported in heart transplant patients.

We report a 22-year-old women hospitalized owing to diabetic ketoacidosis associated with acute pancreatitis 7 months after a heart transplant. Her immunosuppression included tacrolimus. She was admitted with complaints of polydipsia, anorexia, and abdominal pain of 3 days’ duration. Her initial laboratory test revealed a toxic level of tacrolimus (> 30 ng/mL), severe hyperglycemia (39 mmol/L), severe metabolic acidosis (pH 6.9), and ketonuria, although diabetes mellitus had never been diagnosed. Serum amylase and lipase levels and abdominal computed tomography suggested the presence of acute pancreatitis. After correcting the diabetic ketoacidosis and getting the tacrolimus level to the normal range, she was discharged home. Three months later, insulin was replaced with oral hypoglycemic agents. Pancreatitis can present with diabetic ketoacidosis in the recipient of a heart transplant treated with tacrolimus. Clinicians should pay more attention to tacrolimus levels and the risk of pancreatitis.