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Cyclophosphamide (oral and injection)

Generic name: cyclophosphamide (oral/injection) [ sye-kloe-FOSS-fa-mide ]
Brand names: Cytoxan, Neosar, Cytoxan Lyophilized
Dosage forms: intravenous powder for injection (1 g; 2 g; 500 mg), intravenous solution (200 mg/mL), ... show all 3 dosage forms
Drug class: Alkylating agents

Medically reviewed by on Nov 28, 2022. Written by Cerner Multum.

What is cyclophosphamide?

Cyclophosphamide is used to treat several types of cancer.

Cyclophosphamide is also used to treat minimal change nephrotic syndrome (kidney disease) in children who cannot use other treatments or when other treatments have failed.

Cyclophosphamide may also be used for purposes not listed in this medication guide.

Cyclophosphamide side effects

Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Cyclophosphamide may cause serious side effects. Call your doctor at once if you have:

  • new worsening cough, shortness of breath, trouble breathing while lying down;

  • a light-headed feeling, like you might pass out;

  • pink or red urine, pain or burning when you urinate;

  • bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds;

  • any wound that will not heal;

  • heart problems--swelling, rapid weight gain, pounding heartbeats or fluttering in your chest;

  • liver problems--loss of appetite, stomach pain (upper right side), bloating, dark urine, jaundice (yellowing of the skin or eyes);

  • low sodium level--headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady; or

  • low blood cell counts--fever, chills, tiredness, blisters or ulcers in your mouth, skin sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed or short of breath.

Common side effects of cyclophosphamide may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


You should not use cyclophosphamide if you have a bladder obstruction or other urination problems.

Before taking this medicine

You should not use cyclophosphamide if you are allergic to it, or if you have:

  • a bladder obstruction.

Tell your doctor if you have ever had:

  • a weak immune system (caused by disease or by using certain medicines);

  • an active or chronic infection (including a bladder infection);

  • bladder problems;

  • kidney disease (or if you are on dialysis);

  • lung disease;

  • heart disease;

  • liver disease; or

  • if you are receiving other cancer treatments or radiation.

Using cyclophosphamide may increase your risk of developing other types of cancer such as bladder cancer, thyroid cancer, or leukemia. Talk with your doctor about your specific risk.

Cyclophosphamide can harm an unborn baby if the mother or the father is using cyclophosphamide.

  • If you are a woman, do not use cyclophosphamide if you are pregnant. Use effective birth control to prevent pregnancy while you are using this medicine and for at least 1 year after your last dose.

  • If you are a man, use effective birth control if your sex partner is able to get pregnant. Keep using birth control for at least 4 months after your last dose.

  • Tell your doctor right away if a pregnancy occurs while either the mother or the father is using cyclophosphamide.

This medicine may affect fertility (ability to have children) in both men and women. However, it is important to use birth control to prevent pregnancy because cyclophosphamide can harm an unborn baby.

Cyclophosphamide may cause you to stop having menstrual periods. Your periods should return to normal within a few months after you stop using cyclophosphamide. However, older women may have early menopause due to this effect. Talk to your doctor about this risk.

You should not breastfeed while you are using this medicine.

How is cyclophosphamide given?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Cyclophosphamide oral is taken by mouth.

Cyclophosphamide injection is given as an infusion into a vein. A healthcare provider will give you this injection.

Drink plenty of liquids each day to prevent harmful effects on your bladder.

Cyclophosphamide affects your immune system. You may get infections more easily, even serious or fatal infections. Your doctor will need to examine you on a regular basis.

Cyclophosphamide can lower your blood cell counts. Your blood will need to be tested often. Your cancer treatments may be delayed based on the results.

If you need surgery, tell the surgeon ahead of time that you are using cyclophosphamide. You may need to stop using the medicine for a short time.

Ask your doctor or pharmacist how to safely handle this medicine. Cyclophosphamide can be harmful if it gets on your skin. If this occurs, wash thoroughly with soap and water.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

For cyclophosphamide oral: Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Call your doctor for instructions if you miss a dose of cyclophosphamide injection.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include mouth sores, trouble breathing, fast heartbeats, rapid weight gain, stomach pain, or yellowing of your skin or eyes.

What should I avoid while using cyclophosphamide?

Avoid driving or hazardous activity until you know how cyclophosphamide will affect you. Your reactions could be impaired.

Avoid being near people who are sick or have infections. Tell your doctor at once if you develop signs of infection.

What other drugs will affect cyclophosphamide?

Tell your doctor about all your current medicines. Many drugs can affect cyclophosphamide, especially:

This list is not complete and many other drugs may affect cyclophosphamide. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Frequently asked questions

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.