Cytoxan (Cyclophosphamide) – Oral

What Is Cytoxan?

Cytoxan (cyclophosphamide) is an orally administered prescription medication pill used to treat a variety of cancers, such as Hodgkin's lymphoma (Hodgkin's disease), non-Hodgkin's lymphoma (NHL), multiple myeloma (MM), leukemia, and breast carcinoma. Cytoxan is also used for the treatment of pediatric nephrotic syndrome.

Cytoxan is used alone or alongside other cancer-fighting drugs and is approved for use in adults and children.

Cytoxan contains the active ingredient, cyclophosphamide, which is categorized as an alkylating agent. Alkylating agents are a type of chemotherapy that works by stopping cancerous cells from duplicating inside the body by damaging a cell's genetic material (DNA). This process leads to the death of these cells.

Cytoxan is a prescription medication, so it cannot be purchased over-the-counter (OTC).

However, the active ingredient cyclophosphamide is available as a therapeutically equivalent, generic alternative to brand-name Cytoxan. Generic cyclophosphamide is available in capsule (oral) form.

Brand-name Cytoxan comes in the form of a swallowable, oral tablet.

Drug Facts

Generic Name: Cyclophosphamide

Brand Name: Cytoxan

Drug Availability: Prescription

Administration Route: Oral

Therapeutic Classification: Antineoplastic agent

Available Generically: Yes

Controlled Substance: No

Active Ingredient: Cyclophosphamide

Dosage Form: Capsule, tablet

What Is Cytoxan Used For?

The Food and Drug Administration (FDA) has approved Cytoxan for the treatment of several types of malignant diseases (cancers) in both adults and children.

Approved lymphomas (or cancers of the lymphatic system) include:

  • Hodgkin’s lymphoma: Cancer that affects the lymphatic system, which is part of the body's immune system
  • NHL: Cancer that begins to spread in the lymphatic system, but is marked differently than Hodkin's lymphoma as it affects a different lymphocyte
  • Mixed-cell type lymphoma: A slow-growing type of B-cell NHL
  • Histiocytic lymphoma: An aggressive, fast-moving form of non-Hodgkin's lymphoma
  • Mycosis fungoides (cutaneous T-cell lymphoma): The most common form of a type of blood cancer 
  • Burkitt’s lymphoma: A rare but highly aggressive form of B-cell NHL

Other cancers Cytoxan treats include:

  • MM: Cancer that forms in a type of white blood cell (WBC) called plasma cells
  • Types of leukemia: Cancer of blood-forming tissues, including bone marrow
  • Neuroblastoma: Cancer that develops from immature nerve cells found in the adrenal glands
  • Cancer of the ovaries
  • Retinoblastoma (RB): Cancer that begins in the back of the eye (the retina)
  • Breast carcinoma: Cancer that forms in the cells of the breasts

Finally, Cytoxan may be used to treat minimal change nephrotic syndrome in children, if they did not have an adequate response to or weren’t able to tolerate adrenocorticosteroid therapy.

How to Take Cytoxan

You’ll most likely take Cytoxan once per day. Capsules and tablets need to be swallowed whole, not crushed, cut, or chewed.

Take Cytoxan in the morning with plenty of water. Cyclophosphamide can be damaging to your kidneys and bladder, so it’s essential to stay very hydrated while you’re on this medication.

Taking it in the morning ensures that you’ll have time throughout the day to consume plenty of fluids to minimize the risk of damage.

If someone else is helping you with your medications, like a caregiver, they should wear gloves when handling cyclophosphamide containers and capsules, since it is a cytotoxic drug.

If a capsule breaks open and contact occurs with the contents, wash your hands right away and instruct a caregiver to do the same.


Store Cytoxan at room temperature (between 68 and 77 degrees F) in the original container with the lid on, out of reach of children and pets.

Avoid storing your pill bottle in an area that's suspectible to high levels of heat and moisture, such as the bathroom.

If you’re traveling by plane, you’ll want to keep Cytoxan in your carry-on luggage so that you aren’t separated from it in case your checked luggage happens to go missing.

If you’re traveling by car, take care not to leave your pill bottle in especially hot or cold temperatures for long periods of time, like overnight in the car.

Off-Label Uses

Cyclophosphamide has been around for decades, having first been approved in the United States in 1959.

Besides its FDA-approved indications, Cytoxan has been used off-label, that is, for conditions not approved by the FDA to be treated with Cytoxan but that may be helped by the drug.

These include some autoimmune conditions, such as rheumatoid arthritis (RA), lupus, multiple sclerosis (MS), and myasthenia gravis.

How Long Does Cytoxan Take to Work?

As cancer is such a complicated disease, many factors can affect how long Cytoxan takes to work. The type and stage of the cancer being treated, other drugs being used along with Cytoxan, and each individual's response to the drug will affect how long you may have to take Cytoxan before seeing an improvement or possibly going into remission.

What Are the Side Effects of Cytoxan?

Like other medications, Cytoxan may cause side effects. 

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the FDA at or 800-FDA-1088.

Common Side Effects

Side effects you may experience while taking Cytoxan include the following:

  • Neutropenia, the reduction in the number of neutrophils (a certain type of WBC) can make you more susceptible to infections
  • Nausea or vomiting
  • Decreased appetite
  • Abdominal pain
  • Diarrhea
  • Alopecia (hair loss)
  • Pigmentation (color changes on the skin and nails)

Severe Side Effects

Potential serious side effects of Cytoxan include:

  • Immunosuppression: You may be at a higher risk of developing infections since cyclophosphamide suppresses the immune system. These may be bacterial or fungal infections or viruses. While you’re on cyclophosphamide, your healthcare provider should order and monitor certain lab tests regularly to watch for immunosuppression, including a complete blood count.
  • Urinary tract and kidney toxicity: Cyclophosphamide may damage your kidneys and urinary tract. For this reason, it’s essential to drink plenty of water while you take cyclophosphamide, and immediately report pain around your kidneys or urinary tract, and blood in your urine.
  • Cardiotoxicity, or heart damage, is possible with cyclophosphamide. This could include inflammation like myocarditis, heart failure, or arrhythmias (irregular heart rhythm). Talk to your healthcare provider about monitoring your heart health if you have any history of cardiac disease.
  • Pulmonary toxicity, or lung damage, may occur as a result of taking cyclophosphamide. Possible conditions include pneumonitis (inflammation of lung tissue), pulmonary fibrosis (lung diseases that cause tissue to become damaged and scarred), pulmonary veno-occlusive disease (high blood pressure in arteries of the lungs), and others.
  • Secondary cancers may arise during cyclophosphamide treatment, such as urinary tract cancer, myelodysplasia (cancer caused by poorly formed blood cells), acute leukemias (cancers of the blood), lymphomas (cancers in the lymph system), thyroid cancer, and sarcomas (cancer that begins in the bones of soft tissues).
  • Veno-occlusive hepatic (liver) disease has been reported in people taking cyclophosphamide. This is a condition in which some of the veins in your liver are blocked, leading to liver damage. There is a higher risk for this if you have preexisting liver or hepatic disease.
  • Fertility, or the ability to conceive a child, may be impaired in people taking cyclophosphamide. This may depend on the dose, how long you’re on cyclophosphamide and the state of your sexual organs at the time of treatment. Infertility may possibly be reversible, but this is not well known.

Call your healthcare provider right away if you feel like you are experiencing serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency.

Report Side Effects

Cytoxan may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Cytoxan Should I Take?

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The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (tablets):
    • For the treatment of cancer:
      • Adults—Dose is based on body weight and must be determined by your doctor. The usual dose is 1 to 5 milligrams (mg) per kilogram (kg) of body weight per day.
      • Children—Dose is based on body weight and must be determined by your doctor. The usual dose is 1 to 5 mg per kg of body weight per day.


Potential users should note the following before beginning treatment with Cytoxan:

In pregnancy: Cytoxan should not be used in pregnant people. Exposure during pregnancy can cause fetal malformations, miscarriage, fetal growth retardation, and toxic effects in the newborn.

If there is any chance you could be pregnant, you should take a pregnancy test before starting cyclophosphamide. All people, regardless of sex, should use effective birth control while taking cyclophosphamide, and for four months (for males) or a year (for females) after the last dose.

In breastfeeding: Avoid breastfeeding during treatment with cyclophosphamide and for a week after your final dose. The drug is present in breast milk and has been shown to cause diarrhea as well as blood issues such as low white blood cells, platelets, and low hemoglobin in breastfed infants.

In children: Cyclophosphamide should only be used in children when the benefits of treatment outweigh the risk of side effects that come especially with prolonged use. Potential risks include ovarian fibrosis or premature menopause in females, and increased gonadotropin secretion or testicular atrophy (shrinking of the testicles) in males.

In kidney impairment: Make sure to let your healthcare provider know if you have kidney disease. This may cause cyclophosphamide to stay in your system longer, so your dose may need to be adjusted, especially if your creatinine clearance is less than 24 milliliters per minute.

Missed Dose

If you miss a dose of Cytoxan, you can take it as soon as you remember, unless it is closer to being time for your next dose than it is to your missed one.

For example, if you take it at 8 a.m., and you remember at 10 p.m. that you forgot your dose that morning, just skip that dose and take your next one as scheduled at 8 the next morning. Do not double up doses to make up for missed ones.

Overdose: What Happens If I Take Too Much Cytoxan?

No specific antidote, or product to reverse an excess amount of cyclophosphamide in the body, is known. Some of it may be able to be removed by dialysis, a process in which blood is temporarily removed from your body, filtered out, then put back into your circulatory system.

Overdosage will be managed with supportive measures, meaning any symptoms you experience will be treated as they come up, such as infection, immune suppression, or heart damage.

It’s possible for large overdosage to result in some of the more serious potential side effects of cyclophosphamide, like urinary tract damage, veno-occlusive hepatic disease, lung damage, and more.

What Happens If I Overdose on Cytoxan?

If you think you or someone else may have used too much or accidentally swallowed Cytoxan, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses, has a seizure, has trouble breathing, or can’t wake up after using too much or accidentally swallowing Cytoxan, call 911 immediately.


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It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.

While you are being treated with cyclophosphamide, and after you stop treatment with it, do not have any immunizations (vaccines) without your doctor's approval. Cyclophosphamide may lower your body's resistance and the vaccine may not work as well or you might get the infection the vaccine is meant to prevent. In addition, you should not be around other persons living in your household who receive live virus vaccines because there is a chance they could pass the virus on to you. Some examples of live vaccines include measles, mumps, influenza (nasal flu vaccine), poliovirus (oral form), rotavirus, and rubella. Do not get close to them and do not stay in the same room with them for very long. If you have questions about this, talk to your doctor.

Before having any kind of surgery, including dental surgery, or emergency treatment, make sure the medical doctor or dentist in charge knows that you are taking this medicine, especially if you have taken it within the last 10 days.

Cyclophosphamide may cause a temporary loss of hair in some people. After treatment has ended, normal hair growth should return, although the new hair may be a slightly different color or texture.

Cyclophosphamide can temporarily lower the number of white blood cells in your blood, increasing the chance of getting an infection. It can also lower the number of platelets, which are necessary for proper blood clotting. If this occurs, there are certain precautions you can take, especially when your blood count is low, to reduce the risk of infection or bleeding:

  • If you can, avoid people with infections. Check with your doctor immediately if you think you are getting an infection or if you get a fever or chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.
  • Check with your doctor immediately if you notice any unusual bleeding or bruising; black, tarry stools; blood in the urine or stools; or pinpoint red spots on your skin.
  • Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your medical doctor before having any dental work done.
  • Do not touch your eyes or the inside of your nose unless you have just washed your hands and have not touched anything else in the meantime.
  • Be careful not to cut yourself when you are using sharp objects such as a safety razor or fingernail or toenail cutters.
  • Avoid contact sports or other situations where bruising or injury could occur.

Before you have any medical tests, tell the medical doctor in charge that you are taking this medicine. The results of some tests may be affected by this medicine.

What Are Reasons I Shouldn't Take Cytoxan?

Cytoxan is not or may not be the best choice for you if:

  • You’re pregnant: The risk that cyclophosphamide poses to unborn fetuses is likely higher than the benefit gained from taking the medication. Make sure to use effective contraception while you take this drug, and notify your healthcare provider immediately if you think you may be pregnant.
  • You have an allergy to Cytoxan: If you have experienced any hypersensitivity reactions after taking Cytoxan, including anaphylaxis, you should not take it again.
  • You have severe kidney disease or urinary outflow obstruction: Make sure to let your healthcare provider know if you have any kidney disease. This may cause cyclophosphamide to stay in your system longer, so your dose may need to be adjusted if your creatinine clearance is less than 24 milliliters per minute, or you may not be able to take Cytoxan if your kidney function is very low.

What Other Medications Should I Avoid With Cytoxan?

These are drugs that, when taken while you’re also taking cyclophosphamide, may increase the risk of side effects because they also pose a risk for those effects when taken alone.

These drugs may increase the risk of cardiotoxicity, or heart damage, when taken along with cyclophosphamide:

Increased immunosuppression or blood disorders may result from a combined effect of cyclophosphamide and these drugs:

If taking these drugs while you are also on Cytoxan is unavoidable, be vigilant about watching for side effects and let your healthcare provider know as soon as possible if you think you are experiencing any.

What Medications Are Similar to Cytoxan?

Cytoxan is an anticancer drug, technically known as an alkylating agent.

Other alkylating agents include:

  • Leukeran (chlorambucil)
  • Thioplex (thiotepa)
  • Busulfex (busulfan)

There are many other classes of anticancer drugs.

A common anticancer drug class includes antimetabolites, which are further divided into purine antagonists, pyrimidine antagonists, and folate antagonists.

Specific name-brand drugs within this class include:

  • Adrucil (5-FU or fluorouracil)
  • Xeloda (capecitabine)
  • Ara C (cytarabine)
  • Gemzar (gemcitabine)
  • Vidaza (azacitidine)

This is not a list of drugs recommended to take with Cytoxan, though some may be used in combination. Ask your healthcare provider if you have any questions.

Frequently Asked Questions

  • What is Cytoxan used for?

    Cytoxan is approved to treat several lymphomas (cancers of the lymphatic system), such as Hodgkin’s disease and lymphocytic lymphoma. It may also be used to treat multiple myeloma, different types of leukemia, and neuroblastoma.

  • What medications interact with Cytoxan?

    Some medicines may increase the risk of certain side effects more than if you had taken just cyclophosphamide alone.

    Heart damage risk may be increased with other anticancer drugs such as:

    • Adriamycin (doxorubicin)
    • Ara C (cytarabine)
    • Nipent (pentostatin)
    • Herceptin (trastuzumab)

    Your immune system may be further suppressed if you are also taking ACE inhibitors, such as Tysabri (natalizumab), or thiazide diuretics, such as Microzide (hydrochlorothiazide).

  • What are the side effects of Cytoxan?

    Some side effects associated with the use of Cytoxan may include nausea or vomiting, decreased appetite, abdominal pain, diarrhea, and hair loss.

    Additionally, some blood disorders are also possible, such as neutropenia, or a lowering of certain WBCS, called neutrophils.

How Can I Stay Healthy While Taking Cytoxan?

Cytoxan is used to fight against a wide variety of cancers. You may, understandably, feel overwhelmed by the list of potential side effects and precautions.

There are a couple of important things you can do and discuss with your healthcare provider to minimize your risk of side effects from cyclophosphamide.

Since Cytoxan has the potential to damage your kidneys, it’s important to drink plenty of fluids and always stay hydrated while you’re on this drug.

A good general guideline is to try to drink around 2 to 3 liters of water every day, but ask your healthcare provider for a recommendation specific to you.

Mesnex (mesna) is a drug that is considered a cytoprotectant, because it may help protect you from certain side effects of chemotherapy, like urinary tract damage in people taking cyclophosphamide.

Ask your healthcare provider about mesna if they have not already discussed it with you.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Sara Hoffman, PharmD
Sara is a clinical pharmacist that believes everyone should understand their medications, and aims to achieve this through her writing.