Cycloxan 50 Cycloxan contains Cyclophosphamide, a nitrogen mustard alkylating agent. It acts as a prodrug that is converted by hepatic cytochrome P450 enzymes into active alkylating metabolites (phosphoramide mustard and acrolein). These active metabolites cross-link DNA strands and inhibit DNA replication, thereby suppressing cell division in rapidly dividing tumor cells as well as hyperactive immune cells. It is widely prescribed for treating various malignancies—such as lymphoma, leukemia, multiple myeloma, and breast cancer—and as an immunosuppressive agent for autoimmune conditions like severe nephrotic syndrome.