Cyclophosphamide is associated with which toxicity?

• A. Hemorrhagic cystitis
• B. Nephrotoxicity
• C. Pulmonary fibrosis
• D. Cardiotoxicity

Answer: (A)

Cyclophosphamide commonly causes hemorrhagic cystitis because its metabolite acrolein is excreted in the urine and irritates the bladder mucosa, leading to inflammation and bleeding. This risk rises with higher doses or longer treatment; using mesna (a sulfur-containing compound) binds acrolein in the bladder, and aggressive hydration helps wash it out, both of which markedly reduce the incidence and severity of hemorrhagic cystitis.

Nephrotoxicity is more characteristic of some other alkylating agents like ifosfamide, and while cyclophosphamide can have various side effects, hemorrhagic cystitis is the classic teaching point. Pulmonary fibrosis and cardiotoxicity are not typical or defining toxicities of cyclophosphamide, though they can occur with other chemotherapies or at high cumulative doses.