Cyclophosphamide (Systemic)

Brand name(s): Cytoxan

Before Using This Medicine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For cyclophosphamide, the following should be considered:

Allergies-Tell your doctor if you have ever had any unusual or allergic reaction to cyclophosphamide.

Pregnancy-This medicine may cause several different birth defects if either the male or female is taking it at the time of conception or if it is taken during pregnancy. In addition, many cancer medicines may cause sterility. Although sterility occurs commonly with cyclophosphamide, it is usually only temporary.

Be sure that you have discussed this with your doctor before taking this medicine. It is best to use some kind of birth control while you are taking cyclophosphamide. Tell your doctor right away if you think you have become pregnant while taking cyclophosphamide.

Breast-feeding-Cyclophosphamide passes into the breast milk. Because this medicine may cause serious side effects, breast-feeding is generally not recommended while you are taking it.

Children-This medicine has been tested in children and has not been shown to cause different side effects or problems than it does in adults.

Older adults-Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults. Although there is no specific information comparing use of cyclophosphamide in the elderly with use in other age groups, it is not expected to cause different side effects or problems in older people than it does in younger adults.

Other medicines-Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking or receiving cyclophosphamide, it is especially important that your health care professional know if you are taking any of the following:

• Amphotericin B by injection (e.g., Fungizone) or
• Antithyroid agents (medicine for overactive thyroid) or
• Chloramphenicol (e.g., Chloromycetin) or
• Colchicine or
• Flucytosine (e.g., Ancobon) or
• Ganciclovir (e.g., Cytovene) or
• Interferon (e.g., Intron A, Roferon-A) or
• Methotrexate or
• Plicamycin (e.g., Mithracin) or
• Zidovudine (e.g., AZT, Retrovir) or
• If you have ever been treated with radiation or cancer medicines-Cyclophosphamide may increase the effects of these medicines or radiation therapy on the blood

• Cocaine-Cyclophosphamide may increase the effects and toxicity of this medicine

• Cytarabine-Cyclophosphamide may increase the effects of this medicine on the heart and blood

• Azathioprine (e.g., Imuran) or
• Chlorambucil (e.g., Leukeran) or
• Corticosteroids (cortisone-like medicine) or
• Cyclosporine (e.g., Sandimmune) or
• Mercaptopurine (e.g., Purinethol) or
• Muromonab-CD3 (monoclonal antibody) (e.g., Orthoclone OKT3)-There may be an increased risk of infection and development of cancer because cyclophosphamide reduces the body's ability to fight them

• Probenecid (e.g., Benemid) or
• Sulfinpyrazone (e.g., Anturane)-Cyclophosphamide may increase the amount of uric acid in the blood. Since these medicines are used to lower uric acid levels, they may not work as well in patients taking cyclophosphamide

Other medical problems-The presence of other medical problems may affect the use of cyclophosphamide. Make sure you tell your doctor if you have any other medical problems, especially:

• Chickenpox (including recent exposure) or
• Herpes zoster (shingles)-Risk of severe disease affecting other parts of the body

• Gout (history of) or
• Kidney stones (history of)-Cyclophosphamide may increase levels of uric acid in the body, which can cause gout or kidney stones

• Infection-Cyclophosphamide can decrease your body's ability to fight infection

• Kidney disease-Effects of cyclophosphamide may be increased because of slower removal from the body

• Liver disease-The effect of cyclophosphamide may be decreased

• Prior removal of adrenal gland(s)-Toxic effects of cyclophosphamide may be increased, dosage adjustment may be necessary

• Tumor cell accumulation-Increased risk of tumor cells entering the bone marrow, due to bone marrow depression from high doses of cyclophosphamide

Last Revised: 05/22/2002