The short answer
Cyclophosphamide is a type of chemotherapy called an alkylating agent. The body turns it into substances that bind to cancer-cell DNA and stop it from being copied, which makes the cells die. It is used to help treat lymphomas, leukemias, breast cancer, and other cancers, and is usually given as an IV infusion or as pills. Like all cancer medicines it can cause side effects; this page explains the common ones and the warning signs to report. It is educational only and not a substitute for your care team's advice.
Cyclophosphamide is the generic name of this medicine.
It is a type of chemotherapy called an alkylating agent — the body turns it into substances that bind to cancer-cell DNA and stop it from being copied, which makes the cells die.
It is used to help treat lymphomas, leukemias, breast cancer, and several other cancers.
It is usually given as an IV infusion or as pills.
Choose how you want to read this
The whole article, with every detail and caution.
This page is for people starting cyclophosphamide, a chemotherapy drug, and their families. It covers what it treats, how the bladder is protected, fertility, other side effects, and when to call for help.
One old drug, many regimens
Cyclophosphamide was first approved in the US in 1959 and is still widely used. It arrives inactive. The liver converts it into the substances that do the work, and those bind to DNA so a cell can no longer copy itself.
The US label for the injection lists the cancers it is approved for:
- Malignant lymphomas at stage III and IV, including Hodgkin's disease, lymphocytic lymphoma, mixed-cell lymphoma, histiocytic lymphoma, and Burkitt's lymphoma
- Multiple myeloma
- Several leukemias
- Advanced mycosis fungoides
- Neuroblastoma that has spread
- Cancer of the ovary
- Retinoblastoma
- Breast cancer
It is usually given with other drugs rather than alone. It is also used for a kidney condition in children called nephrotic syndrome, which is not cancer.
Protecting the bladder
This is the risk that shapes how the drug is given. One of the substances the liver makes irritates the bladder lining. That can cause hemorrhagic cystitis, meaning bleeding from an inflamed bladder. The label says urinary toxicity can be fatal, and that it can happen with short courses as well as long ones. Long-term damage can include scarring and, later, bladder cancer.
Two things reduce the risk:
- Fluids, so the bladder is flushed and never sits full.
- Mesna, a protective drug that the label says has been used to prevent severe bladder damage.
Your team may ask you to empty your bladder often. Report pink or red urine, burning, or a sudden need to go right away.
Fertility and future pregnancy
Cyclophosphamide interferes with both egg and sperm production and can cause lasting infertility. Whether that happens depends on the dose, how long treatment runs, and your age and hormone status at the time. For some people it is permanent.
If having children later might matter to you, ask about fertility preservation before the first dose, not after. It is a conversation that gets much harder to act on once treatment has started.
Blood counts, infection and the heart
Low blood counts are expected, and with them the risk of infection. Fever needs urgent assessment.
High doses can affect the heart. Inflammation of the heart muscle or its lining, fluid around the heart, heart failure and rhythm disturbances have all been reported. The risk rises with high doses, with older age, and after radiation to the chest. Lung inflammation and a liver problem called veno-occlusive disease are also listed, as are second cancers years later. Low blood sodium can occur and may cause confusion.
By drip or by mouth
The injection goes into a vein; tablets are swallowed. Which one you get depends on the plan.
Some injection products contain alcohol, which the label flags for anyone avoiding it and for people taking medicines that interact with alcohol. Hair loss and nausea are among the most common side effects. Take anti-nausea medicine on the schedule your team gives.
When to get help sooner
- Call 911 or go to an emergency department if you cannot pass urine at all, you are passing clots, or you have chest pain, a racing or uneven heartbeat, or breathlessness that came on fast. Do not drive yourself.
- Ring the number your team gave you the instant your temperature reaches 100.4°F (38°C) or higher, or you get shaking chills — day, night or weekend. Your white cells may be low. CDC says to call your doctor immediately, because an infection during chemotherapy can be life threatening. If that number does not reach a person quickly, go to an emergency department and say you are on chemotherapy.
- Call your care team right away, at any hour, if your urine looks pink, red or brown, it burns to pass it, or you suddenly need the toilet far more often (CDC lists burning with urination as a sign of infection).
- Call your care team right away, at any hour, if you feel confused or unusually muddled. If the confusion comes on suddenly, call 911 (MedlinePlus). Do not drive yourself.
- Call your care team right away, at any hour, if you bruise or bleed more easily than before, or a mouth ulcer or sore throat is making it hard to eat. For emergencies call 911 or go to the ER. Do not drive yourself.
Sources
- https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=34dbffee-80e0-49c3-90e8-95713a0b7fbe
- https://www.cancer.gov/about-cancer/treatment/drugs/cyclophosphamide
- https://www.cdc.gov/cancer-preventing-infections/patients/fever.html
- https://ntp.niehs.nih.gov/ntp/roc/content/profiles/cyclophosphamide.pdf
Common questions
What is Cyclophosphamide?
Cyclophosphamide is a type of chemotherapy called an alkylating agent. The body turns it into substances that bind to cancer-cell DNA and stop it from being copied, which makes the cells die. It is used to help treat lymphomas, leukemias, breast cancer, and several other cancers.
How is Cyclophosphamide given?
It is usually given as an IV infusion or as pills. It can be given into a vein or taken as pills, depending on the plan. Drinking fluids is often encouraged to protect the bladder; your team gives specific instructions. The exact schedule is set by your care team.
What are the common side effects of Cyclophosphamide?
Commonly reported side effects include nausea, hair loss, low blood counts, and bladder irritation. Not everyone gets them, and many can be managed. Tell your care team about anything new or worsening.
Does Cyclophosphamide cure cancer?
That depends on the person, the cancer type, and its stage. For some people a medicine like this can control cancer for a long time or be part of a curative plan; for others the goal is to slow the cancer or ease symptoms. Your care team can explain the goal in your situation.
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Get urgent help
Fever of 100.4°F (38°C) or higher during chemo, severe pain, or trouble breathing: call your cancer care team right away, day or night. Call 911 for an emergency.
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Sources last checked: 2026-08-13 what this meansLast updated: 2026-09-29Next planned review: 2027-01-14
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Editorial review complete — This page completed Cancer Explained's editorial checks (sources, safety, plain language, duplication). It has not been reviewed by a physician or other healthcare professional.
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