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Trade/other name(s): Cytoxan, Neosar, CTX

Why would this drug be used?

Cyclophosphamide is used for the treatment of lymphoma, leukemias, multiple myeloma, mycosis fungoides, neuroblastoma, retinoblastoma, and cancers of the breast and ovary. It is also used to treat some non-cancerous conditions.

How does this drug work?

Cyclophosphamide belongs to a group of chemotherapy drugs called alkylating agents. It helps stop cancer cells from growing, causing them to die.

Before taking this medicine

Tell your doctor…

  • If you are allergic to anything, including medicines, dyes, additives, or foods.
  • If you have any medical conditions such as kidney disease, liver disease (including hepatitis), heart disease, congestive heart failure, diabetes, gout, or infections. Also, be sure your doctor knows if you have had your adrenal glands removed. These conditions may require that your medicine dose, regimen, or timing be changed.
  • If you have ever been treated with radiation or chemotherapy. Your doctor will want to watch you more closely as you receive cyclophosphamide.
  • If you are planning to have surgery in the future. This drug may increase the effects of certain anesthesia drugs (see "Interactions with other drugs", "Precautions").
  • If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. This drug may cause birth defects if either the male or female is taking it at the time of conception or during pregnancy. Check with your doctor about what kinds of birth control can be used with this medicine.
  • If you are breast-feeding. The drug passes into breast milk and may harm the baby.
  • If you think you might want to have children in the future. This drug can cause temporary or permanent sterility in both men and women. Talk with your doctor about the risk with this drug and the options that may preserve your ability to have children.
  • About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

Cyclophosphamide can increase the effects of succinylcholine, a drug used for anesthesia during surgery.

If you get daunorubicin or doxorubicin along with cyclophosphamide, it can increase the risk of heart problems. Doxorubicin given with cyclophosphamide may also increase the risk of bleeding in the bladder.

The anti-inflammatory drug indomethacin (Indocin) can worsen the risk of side effects from cyclophosphamide, and may cause serious problems in blood chemistry and fluid balance.

Taking the heart rhythm drug amiodarone (Cordarone, Pacerone) with cyclophosphamide can greatly increase the risk of serious lung damage.

The following drugs may affect cyclophosphamide levels in your body:

  • anti-seizure drugs phenobarbital, phenytoin, and carbamazepine
  • rifampin (a TB drug)
  • thiotepa, an anti-cancer drug (Thioplex)
  • ticlopidine, a blood thinner (Ticlid)
  • probenecid, a drug that helps other drugs stay in the body longer
  • fluoxetine (Prozac, Serafem)
  • obsessive-compulsive drug treatment fluvoxamine (Luvox)
  • anti-fungal drug ketoconazole
  • acid-blocking drugs omeprazole (Prilosec) and lansoprazole (Prevacid)

Be sure your doctor knows if you start or stop taking any of these drugs while you are getting cyclophosphamide.

Any drugs or supplements that interfere with blood clotting can raise the risk of bleeding during treatment with cyclophosphamide. These include:

  • vitamin E
  • non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve, Naprosyn), and many others
  • warfarin (Coumadin)
  • ticlopidine (Ticlid)
  • clopidogrel (Plavix)

Note that many cold, flu, fever, and headache remedies contain aspirin or ibuprofen. Ask your pharmacist if you aren't sure what is in the medicines you take.

Check with your doctor, nurse, or pharmacist about other medicines, vitamins, herbs, and supplements, and whether alcohol can cause problems with this medicine.

Interactions with foods

No serious interactions with food are known at this time. Check with your doctor, nurse, or pharmacist about whether foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

Cyclophosphamide can be given by mouth either as a pill, or as an injection in a vein. The dose you take will depend on your size and the type of cancer you have. Cyclophosphamide usually is given with other anti-cancer drugs. You will be given anti-nausea medicines before the shot. Take the anti-nausea pill 1 hour before you take your cyclophosphamide and start drinking extra fluids at that time.

Try to take the medicine first thing in the morning with at least a full glass of water to lessen bladder problems. Try to drink at least 1 full glass of fluid every hour, and urinate every 1 to 2 hours. If you have stomach problems, your doctor may tell you to take the pill in smaller doses with food during the day. Talk to your doctor or nurse if the anti-nausea medicine does not stop the nausea or vomiting, so that they can find one that works for you.

Store the medicine in a tightly closed container away from heat and moisture and away from children and pets.


Do not get any immunizations (vaccines), either during or after treatment with this drug, without your doctor's OK. Cyclophosphamide may affect your immune system. This could make vaccinations ineffective, or even lead to serious infections if you get a live virus vaccine during or soon after treatment. Try to avoid contact with people who have recently received a live virus vaccine, such as the oral polio vaccine or smallpox vaccine. Check with your doctor about this.

Tell your doctor or nurse right away if you develop signs of an allergic reaction such as rash, hives (itchy welts), fever and chills, or red blotches on your skin. If you have trouble breathing or swallowing, if you have tightness in your throat, swelling of your tongue, lips, or eyes or other serious symptoms, get emergency help.

Cyclophosphamide can cause bleeding in your bladder. You can help reduce your risk by drinking extra liquids during treatment with this medicine. Avoid taking this drug at night, or at any time you can't spend the whole day drinking extra fluids and emptying your bladder. Your nurse or doctor can give you more instructions. Let your doctor know right away if you see blood in your urine or if you have pain when you urinate. Your doctor will also test your urine to look for small amounts of blood.

Your doctor will likely test your blood throughout your treatment, looking for possible effects of the drug on blood counts (described below) or on other body organs. Based on the test results, you may be given medicines to help treat any effects. Your doctor may also need to reduce or delay your next dose of this drug, or even stop it completely.

This drug can lower your white blood cell count, especially in the weeks after the drug is given. This can increase your chance of getting an infection. Be sure to let your doctor or nurse know right away if you have any signs of infection, such as fever (100.5° or higher), chills, pain when passing urine, a new cough, or bringing up sputum.

This drug may lower your platelet count in the weeks after it is given, which can increase your risk of bleeding. Speak with your doctor before taking any drugs or supplements that might affect your body's ability to stop bleeding, such as aspirin or aspirin-containing medicines, warfarin (Coumadin), or vitamin E. Tell your doctor right away if you have unusual bruising, or bleeding such as nosebleeds, bleeding gums when you brush your teeth, or black, tarry stools.

In rare cases, this drug may damage the heart. Call your doctor right away if you retain fluid (swollen feet or ankles), have trouble getting your breath, or if you notice rapid weight gain.

If you need surgery of any kind, and you have had a dose of cyclophosphamide within the last 10 days, be sure that the doctor or dentist knows that you are taking this drug.

Because of the way this drug acts on cells in the body, it may increase your long-term risk of getting a second type of cancer, such as leukemia or bladder cancer. This is rare, but if it does occur it would probably be years after the drug is used. If you are getting this drug, your doctor feels this risk is outweighed by the risk of what might happen if you do not get this drug. You may want to discuss these risks with your doctor.

Possible side effects

You will probably not have most of the following side effects, but if you have any talk to your doctor or nurse. They can help you understand the side effects and cope with them.


  • low white blood cell count with increased risk of infection*
  • hair loss or thinning, including face and body hair (usually grows back after treatment)
  • nausea
  • vomiting
  • loss of appetite
  • sores in mouth or on lips
  • bleeding from bladder, with blood in urine*
  • diarrhea
  • long-term or short-term infertility (inability to have children) in women and men

Less common

  • low platelet count (mild) with increased risk of bleeding*
  • darkening of nail beds
  • acne
  • tiredness
  • infection
  • fetal changes if you become pregnant while taking cyclophosphamide


  • heart problems with high doses, with chest pain, shortness of breath, or swollen feet
  • severe allergic reactions*
  • skin rash
  • scarring of bladder
  • kidney damage (renal tubular necrosis) which can lead to kidney failure
  • heart damage, with trouble getting your breath, swelling of feet, rapid weight gain*
  • scarring of lung tissue, with cough and shortness of breath
  • second cancer, which can happen years after taking this drug*
  • death from infection, bleeding, heart failure, allergic reaction, or other causes

*See "Precautions" section for more detailed information.

There are other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved before 1984 (FDA cannot verify dates of drugs approved before 1984.)

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.

Last Medical Review: 01/12/2010
Last Revised: 01/12/2010