This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chemotherapy, Subject name: Pharmacology
Hemorrhagic cystitis is caused by: 
Select and explain. 
A. Cyclophosphamide, B. 6 Mercaptopurine, C. 5 Fuorouracil, D. Busulfan
A: Cyclophosphamide
Answer: A: Cyclophosphamide 
Explanation: Cyclophosphamide It is inactive as such: produces few acute effects and is not locally damaging. Transformation into active metabolites (aldophosphamide, phosphoramidemustard) occurs in the liver, and a wide range of anti tumour actions is exeed. It has prominent immunosuppressant propey. Thus, it is one of the most popular anticancer drugs. It is less damaging to platelets, but alopecia and cystitis (due to another metabolite acrolein) are prominent. Chloramphenicol retards the metabolism of cyclophosphamide ESSENTIALS OF MEDICAL PHARMACOLOGY K.D.TRIPATHI SIXTH EDITION PAGE NO:822