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 understand this
The full explanation.
One old drug, many regimens
Cyclophosphamide has been in use since the 1950s and is still everywhere. 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, Hodgkin's disease, lymphocytic lymphoma, mixed-cell lymphoma, histiocytic lymphoma, Burkitt's lymphoma, multiple myeloma, several leukemias, advanced mycosis fungoides, neuroblastoma that has spread, cancer of the ovary, retinoblastoma, and breast cancer. It is usually given with other drugs rather than alone. The tablet label also covers a kidney condition in children that 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. And mesna, a protective drug given with higher doses to mop up the irritant. Empty your bladder often, including overnight if you are asked to. Report pink or red urine, burning, or a sudden need to go, on the same day.
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 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 is common and usually grows back. Nausea can often be well controlled if you take the anti-sickness tablets on schedule rather than waiting.
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.
- 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, and the CDC treats a fever during chemotherapy as a medical emergency that needs antibiotics within hours, not something that waits for clinic hours (CDC). If that number does not reach a person quickly, go to an emergency department and say you are on chemotherapy.
- Call your care team the same day if your urine looks pink, red or brown, it burns to pass it, or you suddenly need the toilet far more often.
- Call your care team within a day or two if you feel confused or unusually muddled, you bruise or bleed more easily than before, or a mouth ulcer or sore throat is making it hard to eat.
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
Words to know
Tap any term to see what it means.
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, tiredness, 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.
Questions to ask your doctor
Being prepared helps you get the most out of your appointments. Save or print these questions.
Tap a question to save it to your list (kept on this device).
Speak With Trained Specialists & Human Navigators
Cancer Explained provides educational guidance, but does not replace trained specialists, social workers, or your medical team.
Talk to a trained cancer information specialist
Free, confidential assistance from NCI Cancer Information Service via phone, chat, or email.
Contact your oncology team
Locate after-hours contact numbers, portal messages, or urgent triage phone lines.
Find a patient navigator
Get one-on-one help with appointments, logistics, translation, and care coordination.
Find a genetic counselor
Discuss inherited mutation risk, family history, and genetic testing options.
Find an oncology social worker
Access emotional counseling, family support groups, and mental health resources.
Find a financial navigator
Locate copay assistance foundations, grant programs, and lodging/travel support.
Find a clinical-trial specialist
Search matching studies and speak with NCI trial information specialists.
Get urgent help
Immediate emergency guidance for fever (>100.4°F during chemo), severe pain, or shortness of breath.
Help Us Improve This Guide
Did this explanation answer your question and help you determine your next step?
Know someone who needs this?
Plenty of people are looking for something like this and do not know where to start. If this would help a friend or someone you love, send it on — we have written an opening line so you do not have to stare at an empty message. You can change every word of it.
Your message is written and sent in your own email or messaging app — we never see who you send it to, and nothing is added to any list.
Knowledge Check
0 of 2 answered
This self-assessment checks understanding of educational content only. It is not medical advice.
Plain-language explanation of the published sources cited on this page. AI-assisted, source-checked, not clinician-reviewed.
Sources last checked: 2026-08-13 what this meansLast updated: 2026-08-18Next planned review: 2027-01-14
How this page was created
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. We do not employ clinicians and do not intend to — our work 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.
General education — varies by person. Answers genuinely differ between people. This page explains what commonly varies and points you to your care team for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
How this page was created
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. We do not employ clinicians and do not intend to — our work 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.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
Read more about our editorial process, our use of AI, and our corrections policy.
Spotted a problem? Report an error — a factual mistake, broken or outdated source, confusing wording, or anything that seems unsafe. Please do not include names, medical record numbers, dates of birth, addresses, or other identifying medical information in your report.
After using this page, do you understand what to do next?
Anonymous — we only record the answer, never who gave it.
Related articles
Still have questions?
Educational answers, plain language
Free to print and share