Cyclophosphamide — DNA-alkylating chemotherapy and immunosuppressant; hemorrhagic cystitis.
Phosphoramide mustard — DNA-crosslinking metabolite responsible for much of cyclophosphamide's antitumor activity; also drives marrow and reproductive toxicity.
Anything that inhibits or induces CYP2B6 shifts the balance between Cyclophosphamide and Phosphoramide mustard.