FAQ: Cyclophosphamide

Why is this medication being recommended?

Cyclophosphamide is part of a class of drugs called immunosuppressants. It suppresses the body's immune response and reduces inflammation in your lungs. Because inflammation is the precursor to fibrosis (scarring), we hope cyclophosphamide will prevent the formation of lung fibrosis and allow the inflamed lung to return to normal.

What special precautions should I follow?

Before taking cyclophosphamide:

  • Tell your doctor and pharmacist if you are allergic to cyclophosphamide or any other drugs.
  • Tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially aspirin and vitamins.
  • Tell your doctor if you have or have ever had kidney disease. The dose of cyclophosphamide may need to be adjusted.
  • Cyclophosphamide may interfere with the menstrual cycle in women and may stop sperm production in men. It can also cause permanent infertility. However, you should not assume that you cannot get pregnant or that you cannot get someone else pregnant. Use a reliable method of birth control to prevent pregnancy, as cyclophosphamide may harm the fetus. Women who are pregnant or breast-feeding should tell their doctors before they begin taking this drug. You should not plan to have children while taking cyclophosphamide or for a while after treatment. Talk to your doctor for further details.
  • Drink plenty of fluids while being treated with cyclophosphamide, as this drug can irritate your kidneys and bladder.
  • Cyclophosphamide has been associated with the development of certain types of cancers. Talk with your doctor about the potential risk of developing cancer.

What side effects can this medication cause?

Side effects from cyclophosphamide are common and include:

  • Darkened and thickened skin
  • Fatigue
  • Loss of appetite or weight
  • Thinned or brittle hair

If you experience any of the following symptoms, call your doctor immediately:

  • Black, tarry stools
  • Blistering of the mouth or skin
  • Chills
  • Congestion
  • Cough
  • Dizziness
  • Fever
  • Nausea and vomiting
  • Painful urination or red urine
  • Rash
  • Shortness of breath
  • Sore throat
  • Swelling of the feet or ankles
  • Unusual bruising or bleeding

What monitoring will I need?

There are two ways of taking cyclophosphamide — by mouth and by intravenous injection. The route of delivery will determine how you are monitored. Your doctor will order regular lab tests to check your response to cyclophosphamide and monitor for toxicity. Your blood counts — white blood cells, red blood cells and platelets — will be checked regularly . Your liver enzymes and urine will be checked regularly as well. Your doctor may order additional tests depending on the results.

For additional information on cyclophosphamide, please visit MedlinePlus.gov.


Reviewed by health care specialists at UCSF Medical Center.

This information is for educational purposes only and is not intended to replace the advice of your doctor or health care provider. We encourage you to discuss with your doctor any questions or concerns you may have.