Side effects of azathioprine

The side effects of azathioprine include:

• marrow suppression, with a reversible neutropenia in 20% of patients
• infection
• nausea
• vomiting
• diarrhoea
• mucosal ulcers
• hepatotoxicity
• acute pancreatitis is a rare complication

Long-term immunosuppressive treatment with azathioprine in transplant patients is associated with an increased risk of cancers, notably non-Hodgkin's lymphoma, squamous cell skin cancer and hepatoma (1). There is evidence from the use of azathioprine in inflammatory bowel disease, that azathioprine did not increase the risk of cancer compared to the general population, nor the risk of colorectal cancer or other cancers compared to that in patients with inflammatory bowel disease who were not given the drug (2).

Reference:

1. Kinlen LJ et al (1979). Collaborative United Kindgom-Australasian study of cancer in patients treated with immunosuppressive drugs. BMJ, 2, 1461-2.
2. Fraser AG, Jewel DP (2000). Long-term risk of malignancy after treatment of inflammatory bowel disease with azathioprine - a 30 year study. Gastroneterol, 118, A1471 (abstract).