Mesna Cyclophosphamide — SCE Medical Oncology MCQ

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EasyOncological EmergenciesMesna CyclophosphamideSCE Medical Oncology

A 62-year-old man receives high-dose cyclophosphamide as part of a conditioning regimen. He develops haemorrhagic cystitis 48 hours later. What preventive measure should have been co-administered?

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Correct answer: A — Mesna (2-mercaptoethane sulfonate sodium) — binds acrolein (the urotoxic metabolite of cyclophosphamide/ifosfamide) in the urinary tract, preventing haemorrhagic cystitis

Acrolein is the urotoxic metabolite of cyclophosphamide and ifosfamide, causing direct urothelial damage and haemorrhagic cystitis. Mesna (a free thiol) binds acrolein in the urinary tract, forming an inert compound. It is MANDATORY with ifosfamide (all doses) and with high-dose cyclophosphamide (stem cell conditioning doses). Standard-dose cyclophosphamide (e.g. AC for breast cancer) does not routinely require mesna but adequate hydration is essential. Mesna has no systemic anti-tumour or anti-toxicity effects — its action is exclusively in the urinary tract.

Reference: BNF Mesna; ESMO Supportive Care; NICE