<prompt> Sterile haemorrhagic cystitis is caused by:BusulfanKetoprofenMethicillinCylclophosphamide  <response>: Ans. is d i.e. CyclophosphamideRef: Harrison 16the p 583 15th e p 435, 650Though Harrison includes Busulfan as a causative agent for hemorrhagic cystitis, no other standard text books of Pharmacology mention it KDT, Goodman Gilman, Katzung and Lawrence. Furthermore in detailed description of Hemorrhagic cystitis it does not mention - BusulfanHarrison states - Hemorrhagic cystitis can develop in patients receiving cyclophosphamide or ifosfamide.Other drugs causing hemorrhagic cystitisCarmustineChlorambucilExtended spectrum penicillins Nitrogen mustard VincristineRemember these following 2 very important points: -Hemorrhagic cystitis due to cyclophosphamide is attributed to the presence of its metabolite ACROLEIN in urine.Hemorrhagic cystitis due to cyclophosphamide can be prevented by -I. V. injection of MESNA Sodium - 2 - mercapto ethane sulfonate and adequate hydration.Also knowHemorrhagic cystitis is also seen in patients who undergo Bone marrow transplantation BMTIn BMT settingsEarly onset hemorrhagic cystitis - dt drugs eg. cyclophosphamide late onset hemorrhagic cystitis - dt polyoma virus BKV or adenovirus type II 