Warning(s)
Cyclophosphamide is a chemotherapy and immune-suppressing drug. It can cause serious side effects. Read these safety points and talk with your care team.
- Allergy alert: Do not use if you have had an allergic reaction to cyclophosphamide.
- Blood counts: This drug can lower white cells, red cells, and platelets. Low counts raise the risk of infection, anemia, and bleeding.
- Infection risk: Wash hands often and avoid people who are sick. Call your care team if you get fever, chills, a new cough, sore throat, or a wound that will not heal.
- Bleeding risk: Easy bruising, nosebleeds, bleeding gums, or blood in stool or urine can happen. Report unusual bleeding right away.
- Bladder toxicity: It can irritate or injure the bladder (hemorrhagic cystitis). Call immediately for blood in urine or pain when passing urine.
- Heart effects: Rare but serious heart problems, including heart failure, can occur. Seek urgent care for chest pain, shortness of breath, rapid weight gain, or swelling in legs.
- Liver effects: Watch for dark urine, yellow skin or eyes, right‑upper belly pain, poor appetite, or vomiting.
- Lung effects: New or worse shortness of breath, cough, or fever can be serious. Contact your team right away.
- Low sodium (SIADH): Headache, confusion, memory trouble, weakness, cramps, or seizures need urgent attention.
- Secondary cancers: A small increased risk of new cancers has been reported after treatment.
- Vaccines: Live vaccines may not be safe, and other vaccines may work less well. Check with your care team before any shots.
- Driving/vision: Avoid driving or tasks needing clear vision until you know how the drug affects you.
- Pregnancy: Can harm an unborn baby or cause pregnancy loss. A pregnancy test is usually done before starting.
- Birth control: If you can become pregnant, use effective birth control during treatment and for 12 months after your last dose. If your sex partner can become pregnant, use birth control during treatment and for the time your care team recommends.
- Breastfeeding: Do not breastfeed during treatment and for 1 week after the last dose.
- Fertility: It may lower fertility in all sexes. Periods may stop or menopause may occur earlier. Some changes may be long‑term.
- Older adults: Side effects can be more common. Extra monitoring may be needed.
- Drug interactions: Tell your care team about all medicines, vitamins, and herbs you take.
- Medical history: Tell your team if you have bone marrow problems, very low blood counts, or trouble passing urine.
- Injection note: Some IV products contain alcohol.
Kind of Cancers It Is Used For (not a complete list)
Doctors use cyclophosphamide alone or with other drugs for many cancers. It is also used for certain immune conditions, such as nephrotic syndrome.
- Lymphomas (Hodgkin and non‑Hodgkin)
- Leukemias (such as chronic lymphocytic leukemia and some acute leukemias)
- Multiple myeloma
- Breast cancer
- Ovarian and other gynecologic cancers
- Soft tissue sarcomas
- Some childhood cancers (such as neuroblastoma, Wilms tumor, retinoblastoma)
Your exact use depends on your cancer type and treatment plan.
Mechanism of Action
- Cyclophosphamide is an alkylating agent (a type of chemotherapy).
- It is a prodrug that is changed by your liver into active compounds.
- These compounds attach to DNA and form cross‑links. This blocks cancer cells from copying and dividing, which leads to cell death.
- It also suppresses parts of the immune system, which is why it is used for some non‑cancer conditions.
- One breakdown product (acrolein) can irritate the bladder. Your care team may use strategies to protect your bladder.
Common Side Effects
Not everyone gets all of these effects. Many are manageable. Tell your care team about side effects that are severe or do not go away.
- Nausea, vomiting, decreased appetite, or diarrhea
- Mouth sores or sore throat
- Hair loss (often temporary)
- Skin or nail color changes
- Tiredness or weakness
- Changes in taste or appetite
- Low blood counts, which can lead to infections, anemia, or easy bruising
- Headache or dizziness
- Irritation when passing urine
This is not a full list of side effects. Your team will monitor your blood counts and organ function during treatment.
Learn more about cyclophosphamide on MedlinePlus
Last reviewed: 2025-12-17
