Increased rates of early adverse reaction to azathioprine in patients with Crohn's disease compared to autoimmune hepatitis: a tertiary referral center experience.

Objectives: Idiosyncratic drug hypersensitivity may occur at increased rates in specific patient populations. Azathioprine has a significant early adverse reaction (EAR) profile, which includes an acute syndrome of constitutional symptoms, fever, rash, and acute pancreatitis and often requires discontinuation of drug. EAR precludes azathioprine use in patients with Crohn's disease (CD) and autoimmune hepatitis (AIH).