Which side effect often accompanies cyclophosphamide?

Hemorrhagic cystitis is a well-documented side effect associated with cyclophosphamide, particularly when given at high doses or over a prolonged treatment period. This side effect arises due to the metabolites of cyclophosphamide, which can irritate the bladder lining, leading to inflammation and damage. The presence of blood in the urine is a key symptom of this condition, indicating that the bladder is compromised.

While nausea, gastrointestinal upset, and cough are potential side effects of various chemotherapy agents, they are not specifically linked to cyclophosphamide. Nausea and gastrointestinal upset are common issues seen with many chemotherapy drugs due to their effects on rapidly dividing cells in the gastrointestinal tract, but they are not the hallmark side effects of cyclophosphamide. Coughing can occur due to numerous reasons, including infections or other unrelated side effects, and does not have a direct correlation with cyclophosphamide treatment. In contrast, hemorrhagic cystitis directly connects to the pharmacological action of cyclophosphamide, making it the most relevant side effect in this context.