What are the long-term side effects of cyclophosphamide use?

The long-term side effects of cyclophosphamide (Cytoxan) are damage to the bladder and the bone marrow. Bladder cancer is a well-known risk and continues to arise at least 10-15 years after the drug was given. Periodic urinalysis is considered a good screen, such that a normal urinalysis is very reassuring; however, any blood seen on urinlysis that cannot be confidently attributed to the kidney should be followed by cystoscopy to visualize the bladder and rule out cancer. Damage to the bone marrow can result in chronically low white blood cell counts (with risk of infection), red blood cell counts (anemia, with fatigue), and platelet counts (risk of bleeding), and patients are also at increased risk of lymphoma and leukemia. All of that being said, the risk of all of these long-term side effects is related to the total dose, and most of the patients who have had such problems took Cytoxan for much longer than 6 months.

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