Cyclophosphamide — Drug Monograph

Brand names: Cytoxan, Neosar

Drug class: Alkylating Agent

Mechanism of Action

Prodrug bioactivated in the liver by CYP2B6/CYP3A4 to active alkylating metabolites (phosphoramide mustard and acrolein). These cross-link DNA strands, inhibiting replication and triggering apoptosis. Cell-cycle non-specific.

FDA Indications

• Malignant lymphomas (Hodgkin and non-Hodgkin lymphoma)
• Multiple myeloma
• Leukemias (CLL, CML, AML)
• Mycosis fungoides
• Neuroblastoma
• Adenocarcinoma of the ovary
• Retinoblastoma
• Breast cancer

Common Side Effects

• Myelosuppression (neutropenia, thrombocytopenia, anemia)
• Nausea and vomiting (moderate-to-high emetic risk)
• Alopecia (dose-dependent; reversible)
• Amenorrhea / gonadal suppression
• Anorexia and mucositis
• SIADH and hyponatremia (high-dose IV)

Clinical Pearl

Mesna (sodium 2-mercaptoethane sulfonate) binds acrolein in the urine and is required for IV doses >1 g/m². The standard mesna dose is 60–160% of the cyclophosphamide dose, divided over the dosing period.

Related Therapies & Mechanisms

• Doxorubicin (Adriamycin) — Breast
• Bendamustine (Treanda) — Alkylating Agent · Lymphoma
• Methotrexate (Trexall) — Breast
• Etoposide (VePesid) — Lymphoma