From the Research
Azathioprine does have a warning for an increased risk of tumors, including lymphoma and skin tumors, although it does not have a specific "black box" warning for tumors. This warning is based on studies that have shown an increased risk of cancer in patients taking azathioprine, particularly those with a history of immunosuppression or inflammatory bowel disease 1, 2. The mechanism is thought to be related to the immunosuppressive effects of azathioprine, which may increase the risk of tumor growth and development. Some studies have suggested a dose-response relationship between azathioprine use and cancer risk, with higher doses and longer durations of treatment associated with a greater risk of tumors 3, 4. However, other studies have found no significant increase in cancer risk with azathioprine use, particularly in patients with inflammatory bowel disease 4. It's worth noting that the FDA has issued "black box" warnings for other drugs, including topical calcineurin inhibitors, due to concerns about an increased risk of cancer 5. Patients taking azathioprine should be informed about the potential risk of tumors and should report any symptoms such as a lump, difficulty swallowing, or shortness of breath, which could indicate tumor growth. Key points to consider when prescribing azathioprine include:
- The patient's history of immunosuppression or inflammatory bowel disease
- The dose and duration of azathioprine treatment
- The patient's overall risk of cancer
- The potential benefits and risks of azathioprine treatment.