BRAND NAME: Cytoxan
DRUG CLASS AND MECHANISM: Cyclophosphamide is a drug that is used primarily for treating several types of cancer. In order to work, cyclophosphamide first is converted by the liver into two chemicals, acrolein and phosphoramide. Acrolein and phosphoramide are the active compounds, and they slow the growth of cancer cells by interfering with the actions of deoxyribonucleic acid (DNA) within the cancerous cells. It is, therefore, referred to as a cytotoxic drug. Unfortunately, normal cells also are affected, and this results in serious side effects. Cytoxan also suppresses the immune system and is also referred to as immunosuppressive.

GENERIC AVAILABLE: Yes

PRESCRIPTION: Yes

PREPARATIONS: Powder for intravenous injection (100 mg), tablets of 25 and 50 mg.

STORAGE: Powder and tablets should be stored at room temperature, 15-30癈 (59-86癋). Solutions prepared with bacteriostatic water are usable up to 24 hours if stored at room temperature and up to 6 days if stored in the refrigerator.

PRESCRIBED FOR: Cyclophosphamide is used for the treatment of several types of cancers and often in combination with other drugs to treat breast cancer, leukemia and ovarian cancer. It also is approved for treating nephrotic syndrome (a disease of the kidneys) in children. Unapproved uses include the treatment of Wegener's granulomatosis, severe rheumatoid arthritis, lupus erythematosus, advanced mycosis fungoides, and a number of forms of vasculitis.

DOSING: The usual initial dose for adults and children is 40-50 mg/kg administered intravenously over 3-5 days in divided doses. The usual oral dose is 1-5 mg/kg daily. Subsequent maintenance doses are adjusted based on the response of the tumor to treatment and the side effects.

DRUG INTERACTIONS: Allopurinol (Zyloprim) enhances the ability of cyclophosphamide to reduce production of blood cells from the bone marrow. (See below.)

Cyclophosphamide increases the occurrence of heart failure that is caused by doxorubicin (Adriamycin), increases the action of blood thinners such as coumarin (Coumadin), and decreases the effects of quinolone antibiotics (Cipro).

PREGNANCY: Use of cyclophosphamide during pregnancy may affect the fetus. Fetuses exposed to cyclophosphamide may be born with missing fingers, toes and a poorly-developed heart. Exposure in the second or third trimester may be less risky.

NURSING MOTHERS: Cyclophosphamide is excreted in breast milk and could cause serious problems in the nursing infant.

SIDE EFFECTS: Side effects of cyclophosphamide include hair loss, vomiting, diarrhea, mouth sores, sterility and jaundice.

Cyclophosphamide causes kidney failure, and it also may affect the heart and lungs. Cyclophosphamide suppresses production of blood cells from the bone marrow, including white blood cells (leukopenia), red blood cells (anemia) and platelets (thrombocytopenia). Leukopenia reduces the ability of the body to fight infection, thrombocytopenia impairs the ability of blood to clot, and anemia reduces the ability of blood to carry oxygen.

Cyclophosphamide also may cause inflammation of the urinary bladder with bleeding (hemorrhagic cystitis). This can result in lower abdominal pain from the bladder, problems urinating due to blood clots, and anemia due to loss of blood.