Haemorrhagic cystitis is caused by

Ans. is 'a' i.e., Cyclophosphamide Hemorrhagic cystic is most commonly associated with cyclophosphamide (seen in 5-10 % of patients).In Harrison drugs causing hemorrhagic cystitis have been listed and this also includes Busulphan.Still, I prefer cyclophosphamide as the answer because none of the pharmacology books (This even includes Goodman & Gilman) mention hemorrhagic cystitis as an adverse effect of Busulfan.More question on this topic: -Hemorrhagic cystitis has been attributed to cyclophosphamide because of the presence of acrolein.Adequate hydration and intravenous injection of MESNA (Sodium 2-mercaptoethane sulfonate) minimize this problem.