Rapid development of pancreatitis following reuse of 6-mercaptopurine.

A patient with Crohn's disease developed acute pancreatitis 4 h after retaking one 50 mg dose of orally administered 6-mercaptopurine (6-MP). All seven previously reported patients who were rechallenged with 50 mg or more of 6-MP developed pancreatitis within 48 h. These findings suggest that 6-MP can produce pancreatitis due to an idiosyncratic immune-mediated response. Patients with this complication should not reuse 6-MP.