Acute pancreatitis in a patient treated with imatinib and gefitinib.

To our knowledge, this is the first case in the medical literature of acute pancreatitis possibly induced by an interaction between imatinib and gefitinib. The interaction most likely arose because imatinib is a CYP2D6 inhibitor and could therefore impair the metabolism of gefitinib (a CYP2D6 substrate) and increase its serum concentration. This interaction is extremely rare. However, due to its severity, hepatic and pancreatic function should be carefully monitored in patients treated with imatinib and/or gefitinib and other inhibitors or inducers of CYP2D6 and CYP3A4.