Cyclophosphamide Health Article

Definition

Cyclophosphamide is an anticancer (antineoplastic) agent. It also acts as a suppressor of the immune system. It is available under the brand names Cytoxan and Neosar.

Purpose

Cyclophosphamide is approved by the Food and Drug Administration (FDA) to treat several forms of cancer. These include:

• breast cancer
• leukemia
• malignant lymphoma
• multiple myeloma
• ovarian cancer
• soft tissue sarcoma
• mycosis fungoides
• nephrotic syndrome
• neuroblastoma
• Wilms' tumor
• retinoblastoma

Cyclophosphamide has activity against a wide variety of other cancers and conditions not specifically approved by the FDA, and patients should be aware that it may be commonly prescribed for these other disease states:

• bone cancer
• cervical cancer
• endometrial cancer
• germ cell tumors
• gestational trophoblastic tumors
• histiocytosis X
• lung cancer
• prostate cancer
• testicular cancer
• Wilms' tumor

Description

Cyclophosphamide chemically interferes with the synthesis of the genetic material (DNA and RNA) of cancer cells by cross-linking DNA strands, preventing these cells from being able to reproduce and continue the growth of the cancer.

Recommended dosage

Cyclophosphamide may be taken either orally (in pill form) or as an injection into the vein. The dosage prescribed may vary widely depending on the patient, the cancer being treated, and whether or not other medications are also being taken.

A typical oral dosage for adults is 1 to 5 mg per kg of body weight per day for initial and maintenance dose, or 400 to 1000 milligrams per squared meter of body surface area for four to five days every three to four weeks. A typical dosage by injection is 40 to 50 mg per kg, divided in several smaller doses, for two to five days. The dose for patients receiving bone marrow transplant may be as high as 60 mg per kg per day for two days.

Precautions

Cyclophosphamide should be taken on an empty stomach. If stomach irritation occurs, it should be taken with small amounts of food or milk. Cyclophosphamide should always be taken with plenty of fluids.

Cyclophosphamide can cause an allergic reaction in some people. Patients with a prior allergic reaction to cyclophosphamide should not receive this drug.

Cyclophosphamide can cause serious birth defects if either the man or the woman is taking this drug at the time of conception or if the woman is taking this drug during pregnancy. Contraceptive measures should be taken by both men and women while on this drug. Sterility is a common side effect of cyclophosphamide. This sterility is dependent upon the dose, duration of therapy, and state of function of the ovary or testicle at the time of administration of the drug. The sterility may be irreversible in some patients.

Because cyclophosphamide is easily passed from mother to child through breast milk, breast feeding is not recommended while under treatment.

Cyclophosphamide suppresses the immune system and interferes with the normal functioning of certain organs and tissues, and its excretion from the body is dependent on a normal functioning kidney and liver. For these reasons, it is important that the prescribing physician is aware of any of the following pre-existing medical conditions:

• a current case of, or recent exposure to, chicken pox
• herpes zoster (shingles)
• all current infections
• kidney disease
• liver disease
• a prior removal of one, or both, adrenal gland (s)

Also, because cyclophosphamide is such a potent immunosuppressant, patients taking this drug must exercise extreme caution to avoid contracting any new infections.