Busulfan is a chemotherapy drug used mainly for blood cancers and before stem cell or bone marrow transplants. It is an alkylating agent that damages cancer cell DNA. You may get it as an injection (IV) or as tablets, depending on your treatment plan.
Brand Name(s)
- United States: Busulfex (injection); Myleran (tablets)
- Canada: Myleran; PMS-Busulfan
Warning(s)
- Severe low blood counts: This drug can sharply lower white blood cells, red blood cells, and platelets. This may lead to serious infections, anemia, or bleeding. Your care team will check blood work often.
- Injection is part of transplant care: IV busulfan is used as part of a plan that includes a stem cell transplant. The transplant helps lower the risk of life‑threatening problems after high‑dose chemotherapy.
- Infection risk: Wash your hands often and avoid people who are sick. Call your care team right away if you have fever, chills, cough, burning when urinating, mouth sores, or a wound that will not heal.
- Bleeding risk: You may bruise or bleed more easily. Use a soft toothbrush and an electric razor. Report black or tarry stools, vomiting blood or coffee‑ground material, nosebleeds that don’t stop, or new/unusual bruising.
- Liver problems: Serious liver injury can happen and can be life‑threatening. Call your team if you have dark urine, yellow skin or eyes, right‑sided belly pain, severe nausea/vomiting, light‑colored stools, or unusual tiredness.
- Lung problems: Busulfan can cause new or worsening cough, fever, and shortness of breath. Get help right away if breathing problems start or worsen.
- Heart problems: Serious heart issues have happened in some people, sometimes after severe stomach upset. Report chest pain, pressure, or a fast heartbeat immediately.
- Seizure risk: Busulfan can raise the chance of seizures. Your team may give medicine to help prevent seizures during treatment.
- Eye problems: Cataracts can rarely occur. Tell your team if you notice changes in eyesight.
- Second cancers: Other cancers may rarely develop later in life after treatment with busulfan.
- Vaccines: Talk with your doctor before any vaccines. Some vaccines may not work as well or may raise infection risk while your immune system is weak.
- Pregnancy and fertility: Busulfan can harm an unborn baby. Use effective birth control during treatment and for the time your doctor recommends after the last dose. It may cause infertility or early menopause. Do not breastfeed while taking this drug.
- Drug interactions: Tell your doctor and pharmacist about all medicines, vitamins, and herbal products you use.
- Dental and medical care: Tell all healthcare providers, including dentists, that you are taking busulfan.
Kind of Cancers It Is Used For (not a complete list)
- Before stem cell or bone marrow transplant (conditioning): Often used for blood cancers, such as acute myeloid leukemia (AML), chronic myeloid leukemia (CML), myelodysplastic syndromes (MDS), and some lymphomas and myeloproliferative neoplasms.
- Leukemia: Used to treat certain types of leukemia, including CML and, in some cases, AML.
Your care team chooses busulfan based on your cancer type, overall health, lab results, and the transplant plan.
Mechanism of Action
- Busulfan is an alkylating agent. It attaches to DNA and forms cross‑links.
- This damage stops cells from copying DNA and dividing, which leads to cell death.
- Cancer cells divide quickly, so they are more sensitive to this damage.
- Before transplant, busulfan helps clear the bone marrow and weaken the immune system so donor stem cells can engraft.
Common Side Effects
Not everyone has all the side effects listed below. Tell your care team about symptoms that bother you or do not go away.
- Very common (all forms): Low blood counts (infection, bleeding, and anemia risk); tiredness or weakness; decreased appetite; nausea or vomiting; diarrhea or constipation; stomach pain; mouth sores or irritation.
- Injection (IV) busulfan: Flushing, headache, dizziness, anxiety, trouble sleeping, back pain, runny or stuffy nose, heartburn, dry mouth, infusion‑site irritation or swelling.
- Tablets: Dry mouth, eyes, skin, or lips; changes in skin color; hair loss.
Call your care team right away if you have:
- Signs of allergic reaction: rash, hives, itching, swelling of the face or throat, wheezing, or trouble breathing.
- Signs of infection: fever, chills, cough with more or discolored sputum, very sore throat, mouth sores, burning with urination, or a wound that will not heal.
- Signs of bleeding: black or red stools, vomiting blood or coffee‑ground material, blood in urine, bleeding gums, or bruises that appear or grow without a cause.
- Severe belly pain, severe nausea or vomiting, chest pain, a very fast heartbeat, severe tiredness, or fainting.
- New or worsening shortness of breath or cough, or fever.
- Yellow skin or eyes, dark urine, light‑colored stools, or right‑sided belly pain.
- Seizures, severe headache, vision changes, confusion, or sudden weakness or trouble speaking.
- Swelling in a leg or arm, chest pain, coughing up blood, or sudden shortness of breath (possible blood clot).
- High blood pressure symptoms (very bad headache, dizziness, changes in eyesight) or signs of high blood sugar (sleepiness, unusual thirst or hunger, frequent urination, fruity breath).
- For tablets: signs of weak adrenal glands (severe dizziness or passing out, severe nausea/vomiting, muscle weakness, mood changes), enlarged breasts, or muscle weakness.
If you have side effects, ask your care team about ways to help, such as nausea medicines, mouth care, skin care, and infection and bleeding precautions.
Last reviewed: 2025-12-15
