Skip to main content

Busulfan (oral/injection)

Generic name: busulfan (oral/injection) [ bue-SUL-fan ]
Brand names: Busulfex, Myleran
Dosage forms: intravenous solution (6 mg/mL), oral tablet (2 mg)
Drug class: Alkylating agents

Medically reviewed by on Apr 25, 2023. Written by Cerner Multum.

What is busulfan?

Busulfan oral (taken by mouth) is used to treat the symptoms of chronic myelogenous leukemia (a type of blood cancer). Busulfan is not a cure for leukemia.

Busulfan injection is used together with a medicine called cyclophosphamide, to prepare your body to receive a stem cell transplant from a donor's bone marrow.

Busulfan may also be used for purposes not listed in this medication guide.


Busulfan affects your immune system. You may get infections more easily, even serious or fatal infections. Call your doctor if you have a fever, chills, cough, mouth sores, or unusual bleeding or bruising.

Busulfan can have long lasting effects on your body. You may need frequent medical tests for a short time after you stop using busulfan.

Before taking this medicine

You should not use busulfan if you are allergic to it.

Tell your doctor if you have ever had:

  • a weak immune system (bone marrow depression) caused by other cancer medications or radiation treatment;

  • epilepsy or other seizure disorder;

  • a head injury; or

  • lung or breathing problems.

Some people treated with busulfan have developed new forms of cancer. Talk to your doctor about your specific risks and benefits of using this medicine.

Busulfan can harm an unborn baby or cause birth defects if the mother or the father is using this medicine.

  • If you are a woman, do not use busulfan if you are pregnant. Use effective birth control to prevent pregnancy while you are using this medicine and for at least 6 months after your last dose.

  • If you are a man, use effective birth control if your sex partner is able to get pregnant. Keep using birth control for at least 3 months after your last dose.

  • Tell your doctor right away if a pregnancy occurs while either the mother or the father is using busulfan.

High-dose busulfan may affect fertility (ability to have children) in women, either temporarily or permanently. Talk with your doctor if you have concerns about this risk.

You should not breastfeed while using this medicine.

How should I use busulfan?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Take the busulfan oral tablet with a full glass of water.

Busulfan injection is given as an infusion into a vein in your upper chest (central IV). A healthcare provider will give you this injection. You will also receive other medicines to help prevent certain side effects of busulfan.

Busulfan can lower blood cells that help your body fight infections and help your blood to clot. Your blood will need to be tested often. Your cancer treatments may be delayed based on the results.

Busulfan can have long lasting effects on your body. You may need frequent medical tests for a short time after you stop using busulfan.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Since busulfan injection is given by a healthcare professional, you are not likely to miss a dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using busulfan?

Avoid being near people who are sick or have infections. Tell your doctor at once if you develop signs of infection.

Busulfan side effects

Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Busulfan may cause serious side effects. Call your doctor at once if you have:

  • easy bruising, unusual bleeding, purple or red spots under your skin;

  • fever, chills, tiredness, sore throat;

  • cough, trouble breathing, chest pain, wheezing;

  • coughing with bloody mucus;

  • pale skin, cold hands and feet;

  • vision problems;

  • persistent cough, congestion, or breathing problems that occur several months or years after using busulfan;

  • a seizure;

  • adrenal gland problems--nausea, vomiting, loss of appetite, weight loss and severe weakness or tired feeling;

  • signs of a heart problem--stomach pain, vomiting, sharp chest pain, trouble breathing;

  • signs of liver problems--weight gain, stomach swelling or tenderness, jaundice (yellowing of the skin or eyes); o

  • signs of an electrolyte imbalance--muscle contractions, muscle weakness, leg cramps, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling.

Common side effects of busulfan may include:

  • fever, chills, headache, weakness;

  • pain;

  • nausea, vomiting, stomach pain, diarrhea;

  • fast heartbeats;

  • changes in your menstrual periods;

  • blisters or ulcers in your mouth, red or swollen gums, trouble swallowing;

  • dry mouth, nose, or throat;

  • dry or thinning skin, darkened skin color;

  • breast swelling;

  • sleep problems (insomnia); or

  • anxiety.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect busulfan?

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

Other drugs may affect busulfan, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.