Busulfan

Say it: byoo-SULL-fan · Brand names: Myleran, Busulfex

Busulfan is a chemotherapy medicine that damages the DNA in blood-forming cells, often used to prepare for a stem cell transplant.

What it is

Busulfan links the strands of DNA together so cells cannot copy themselves. It works strongly on cells in the bone marrow. This clears space for new stem cells during a transplant.

Often used for

• preparing the body for a stem cell transplant
• chronic myeloid leukemia (CML)

How you get it

Before a transplant, busulfan is given through a vein (IV), often every 6 hours or once a day for 4 days, in the hospital. A pill form may be taken at home for chronic myeloid leukemia. Your schedule may be different.

Common side effects and what helps

• Very low blood counts, which raise your risk of infection, bleeding, and tiredness. Wash your hands often.
• Nausea and vomiting. Take your anti-nausea medicine as your team tells you.
• Mouth sores. Keep your mouth clean with gentle rinses and a soft toothbrush.
• Diarrhea. Drink fluids and tell your team if it is frequent.
• Poor appetite. Try small meals.
• Hair loss. It usually grows back.
• Darker skin. This often fades over time.

Call your care team right away if you have

• A fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher, or chills
• A seizure, shaking, or sudden confusion
• Fast weight gain, belly swelling, or pain under the right ribs
• Yellow skin or eyes
• A new cough or shortness of breath
• Bleeding or bruising that will not stop, black or bloody stools, or blood in your urine

Before you start, tell your team

• If you are pregnant, may become pregnant, or are breastfeeding
• If you have ever had a seizure or head injury
• If you have liver problems
• If you have had radiation or other chemotherapy
• All the medicines, vitamins, and herbal products you take

Good to know

• Busulfan can cause seizures. You will get a medicine to prevent seizures during treatment.
• It can cause a serious liver problem where blood vessels in the liver get blocked. Your team will check your weight and liver tests.
• Rarely, it can scar the lungs, even months or years later.
• It usually causes infertility. Talk with your team about fertility before treatment.
• Rarely, it can cause a new cancer years later.

At home

• If you take pills at home, swallow them whole with water.
• 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 long will I be in the hospital?
• What medicine will I get to prevent seizures?
• What signs of liver problems should I watch for?
• Can I save eggs or sperm before treatment?

Side effect guides

• Fatigue (tiredness)
• Nausea and vomiting
• Diarrhea
• 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.