A 52-year-old man receiving cyclophosphamide for non-Hodgkin lymphoma develops painless hematuria on day 10. The most effective agent for preventing this complication is:
- A N-acetylcysteine, which scavenges acrolein in the renal tubules
- B Mesna (2-mercaptoethane sulfonate sodium), which detoxifies acrolein in the bladder ✓
- C Allopurinol, which inhibits xanthine oxidase-mediated acrolein production
- D Amifostine, which directly alkylates acrolein before bladder exposure
Correct answer: B. Mesna (2-mercaptoethane sulfonate sodium), which detoxifies acrolein in the bladder
Explanation
Cyclophosphamide is metabolized to acrolein, a urotoxic metabolite that accumulates in the bladder and causes hemorrhagic cystitis. Mesna is a sulfhydryl compound that is excreted in the urine and reacts directly with acrolein in the bladder lumen, forming a non-toxic thioether complex and neutralizing its urotoxic effects. Aggressive hydration and frequent voiding also help. Mesna has no systemic anti-cancer activity and does not protect other organs from cyclophosphamide toxicity.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
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Written and medically reviewed by the StethoPrep medical team.