Cyclophosphamide (Cytoxan®)

Drug Class- Cytotoxic/Immunosuppressive

Mechanism of Action

Drugs of this class suppress the natural immune system including B and T lymphocyte activity and function.

Diseases Treated with this Medication

This medication is primarily used to treat cancers and nephrotic syndrome. Although not FDA approved, other kidney diseases caused by a disrupted immune system have been treated successfully with this medication including systemic vasculitis and lupus nephritis.

Contraindications

DO NOT take this medication if you are allergic to cyclophosphamide products or if you have a low white blood cell count.  

Common Side Effects

  • Hair loss
  • Nausea and vomiting
  • Decreased appetite
  • Nail damage including darkening of the nails
  • Changes in menstrual period

Serious Side Effects

  •  Bone marrow suppression including
    • Decrease in the number of circulating white blood cells (leukopenia) which may increase your risk of infection
    • Decrease in platelet count (thrombocytopenia) whichmay increase risk your of bleeding
    • Decrease in red-blood cell count 
  • Infertility in males and in females
  • Bladder cancer has beenassociated with long-term therapy (2 to 10 years)

Drug Interactions

Drug NameInteraction
Allopurinol (Zyloprim®) Allopurinol can increase cyclophosphamide blood concentrations leading to increased side effects. Allopurinol on its own may cause bone marrow suppression, nausea and vomiting.
Cyclosporine (Neoral®, Sandimmune®, Gengraff®) Cyclosporine blood concentrations can decrease leading to reduced effectiveness. However, immunosuppression may be enhanced with the combination. Decreases blood concentrations of cyclophosphamide.
Thiazide diuretics (chlorthalidone, hydrochlorothiazide) Thiazides may increase the toxic effects of cyclophosphamide, particularly decreased white blood cell count.

Patient Instructions

  • Females should use two forms of birth control to avoid pregnancy while on this medication because it can cause serious birth defects especially if administered during the first trimester of pregnancy. 
  • This medicine may be taken with food to avoid stomach upset. 
  • Plenty of fluids should be consumed while taking this medication to keep the kidneys working properly and prevent bladder accumulation.
  • Watch for the following symptoms and call your doctor immediately if you experience ANY of them:  itching, swelling in the face or hands, blood in urine or stool, painful urination and discoloration, fever, chills, unusual bleeding, bruising or weakness, yellowing of the eyes or skin