Cyclophosphamide

Say it: sye-kloh-FOSS-fuh-mide

Cyclophosphamide is a chemotherapy medicine that damages the DNA inside cancer cells so they cannot grow.

What it is

Your liver changes cyclophosphamide into its active form. It then sticks to the DNA in cells and links the strands together. Cells that grow fast, like cancer cells, cannot copy themselves and die.

Often used for

• breast cancer
• lymphoma
• leukemia
• multiple myeloma
• ovarian cancer
• some childhood cancers, such as neuroblastoma
• and some other cancers

How you get it

Cyclophosphamide can be given through a vein (IV) over about 30 minutes to a few hours, or taken as a pill at home. Doses into a vein are often given once every 2 to 3 weeks, and pills are often taken daily for a set time. Your schedule may be different.

Common side effects and what helps

• Nausea and vomiting. Take your anti-nausea medicine as your team tells you, and eat small meals.
• Hair thinning or hair loss. It usually grows back after treatment ends. A soft hat or scarf can help.
• Low blood counts, which raise your risk of infection, bleeding, and feeling tired. Wash your hands often.
• Feeling tired. Rest and short walks can help.
• Mouth sores. Rinse with a mild salt and baking soda rinse and use a soft toothbrush.
• Poor appetite. Try small snacks through the day.
• Changes in periods or sperm. Ask your team about fertility before you start.

Call your care team right away if you have

• A fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher, or chills
• Blood in your urine, or pain or burning when you pass urine
• Shortness of breath, a new cough, or chest pain
• Bleeding or bruising that will not stop, black or bloody stools, or blood in your urine
• Swelling in your legs or sudden weight gain
• Vomiting so much you cannot keep fluids down

Before you start, tell your team

• If you are pregnant, may become pregnant, or are breastfeeding
• If you have kidney or liver problems
• If you have had bladder problems or radiation to your pelvis
• If you have heart problems or have had other chemotherapy
• All the medicines, vitamins, and herbal products you take

Good to know

• This medicine can irritate the bladder and cause bleeding. Drinking plenty of fluids and passing urine often helps protect it.
• You will have blood tests to check your blood counts.
• It can harm an unborn baby. Ask your team about birth control during and after treatment.
• It can affect your ability to have children. Talk with your team before treatment if this matters to you.
• Rarely, it can cause heart or lung problems, or a new cancer years later.

At home

• If you take pills, swallow them whole with water. Do not crush, cut, or chew them.
• Many people take the pills in the morning and drink extra fluids during the day. Follow your team's plan.
• If you miss a dose, ask your team what to do.
• Store pills at room temperature in the original bottle, away from children and pets.
• Caregivers should wear gloves if they touch the pills and wash hands after.

Questions to ask

• How often will I get this medicine?
• How much should I drink each day to protect my bladder?
• Will this affect my ability to have children?
• What should I do if I cannot keep fluids down?

Part of these treatment plans

• AC and dose-dense AC
• BV-CHP
• C10403 (CALGB 10403)
• CyBorD
• DA-EPOCH-R
• FCR
• Hyper-CVAD
• R-CHOP
• TC
• VAC/IE

Side effect guides

• Fatigue (tiredness)
• Nausea and vomiting
• Mouth sores
• Appetite loss and weight loss
• Hair loss
• Low white blood cells and infection risk
• Low platelets and bleeding

Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.