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Trade/other name(s): Myleran, Busulfex

Why would this drug be used?

Busulfan is used to treat chronic myelogenous leukemia, some lymphomas, and certain other blood disorders. It may also be prescribed for other uses.

How does this drug work?

Busulfan belongs to the group of chemotherapy drugs known as alkylating agents. It slows or stops cancer cell growth, and causes them to die.

Before taking this medicine

Tell your doctor…

  • If you are allergic to anything, including medicines, dyes, additives, or foods.
  • If you have ever had chemotherapy, or radiation treatment. This can worsen the drug's effect on your bone marrow (blood cells).
  • If you have any medical conditions such as kidney disease, liver disease (including hepatitis), heart disease, congestive heart failure, diabetes, gout, or infections. These conditions may require that your medicine dose, regimen, or timing be changed.
  • If you have ever had seizures or serious head injury. This drug can increase your risk of seizures.
  • If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. This drug may cause birth defects if either the male or female is taking it at the time of conception or during pregnancy. Check with your doctor about what kinds of birth control can be used with this medicine.
  • If you are breast-feeding. The drug may pass into breast milk and harm the baby.
  • If you think you might want to have children in the future. This drug has been reported to cause sterility in some people. Talk with your doctor about the possible risk with this drug and the options that may preserve your ability to have children.
  • About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

If you are taking the anti-fungal drug itraconazole, it can cause your blood levels of this drug to be higher, and cause more bad effects.

Any drugs or supplements that interfere with blood clotting can raise the risk of bleeding during treatment with busulfan. These include:

  • vitamin E
  • non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve, Naprosyn), and many others
  • warfarin (Coumadin)
  • ticlopidine (Ticlid)
  • clopidogrel (Plavix)

Note that many cold, flu, fever, and headache remedies contain aspirin or ibuprofen. Ask your pharmacist if you aren't sure what's in the medicines you take.

Check with your doctor, nurse, or pharmacist about other medicines, vitamins, herbs, and supplements, and whether alcohol can cause problems with this medicine.

Interactions with foods

No serious interactions with food are known at this time. Check with your doctor, nurse, or pharmacist about whether foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

Busulfan tablets are taken by mouth with or without food, at about the same time every day. Your dose depends on your blood counts and your size. You will take a higher dose for the first few weeks of treatment then the dose will be lowered for "maintenance." Your blood counts will be checked often, and depending on your white blood cell count, you may be told to stop the medicine for a while. This medicine is also used in much higher doses when it's given in the vein to wipe out the bone marrow in order to prepare a person for a bone marrow transplant.

Store the medicine in a tightly closed container, away from heat and moisture and out of the reach of children and pets. Make sure that you understand all the instructions from your doctor and that you have the telephone number to call if you have questions. Take this drug exactly as your doctor tells you.


Your doctor will likely test your blood throughout your treatment, looking for possible effects of the drug on blood counts (described below) or on other body organs. Based on the test results, you may be given medicines to help treat any effects. Your doctor may also need to reduce or delay your next dose of this drug, or even stop it completely. Be sure to keep all your appointments for lab tests and doctor visits.

This drug can lower your white blood cell count, especially in the weeks after the drug is given. This can increase your chance of getting an infection. Infections can quickly worsen and become life-threatening. Be sure to let your doctor or nurse know right away if you have any signs of infection, such as fever (100.5° or higher), chills, pain when passing urine, a new cough, or bringing up sputum.

This drug may lower your platelet count in the weeks after it is given, which can increase your risk of bleeding. Speak with your doctor before taking any drugs or supplements that might affect your body's ability to stop bleeding, such as aspirin or aspirin-containing medicines, warfarin (Coumadin), or vitamin E. Tell your doctor right away if you have unusual bruising, or bleeding such as nosebleeds, bleeding gums when you brush your teeth, or black, tarry stools.

This drug may lower your red blood cell count. If this occurs, it usually is a few months after starting treatment. A low red blood cell count (known as anemia) can cause shortness of breath, or make you feel weak or tired all the time. Your doctor may give you medicines to help prevent or treat this condition, or you may need to get blood transfusions.

Do not get any immunizations (vaccines), either during or after treatment with this drug, without your doctor's OK. Busulfan may affect your immune system. This could make vaccinations ineffective, or even lead to serious infections if you get a live virus vaccine during or soon after treatment. Try to avoid contact with people who have recently received a live virus vaccine, such as the oral polio vaccine or smallpox vaccine. Check with your doctor about this.

You may have nausea and vomiting while on this medicine. Your doctor may give you medicine before your treatment to help prevent nausea and vomiting. You will likely also get a prescription for an anti-nausea medicine that you can take at home. It is important to have these medicines on hand and to take them as prescribed by your doctor.

This drug may cause sores in the mouth or on the lips, which often occur within the first few weeks after starting treatment. This can cause mouth pain, bleeding, or even trouble eating. Your doctor or nurse can suggest ways to reduce this, such as changing the way you eat or how you brush your teeth. If needed, your doctor can prescribe medicine to help with the pain.

Let your doctor know if you notice weakness or tiredness for more than a day or two, especially if you have poor appetite, weight loss, nausea, and changes in skin color.

Stop the drug and tell your doctor or nurse right away if you develop signs of an allergic reaction such as rash, hives (itchy welts), headache, dizziness, fever, chills, or red blotches on your skin. If you have trouble breathing or swallowing, if you have swelling or itching in your throat, lips, or mouth, or other serious symptoms, stop the drug and get emergency help.

Because of the way this drug acts on cells in the body, it may increase your long-term risk of getting a second type of cancer, such as leukemia. This is rare, but if it does occur it would likely be years after the drug is used. If you are getting this drug, your doctor feels this risk is outweighed by the risk of what might happen if you do not get this drug. You may want to discuss these risks with your doctor.

In a few people, the drug can cause lung damage which can start a few months up to 10 years after taking it. The lungs can become scarred and inflexible, making it hard to breathe. Let your doctor know right away if you have a cough, low-grade fever, or shortness of breath.

Tell your doctor if you have sudden weakness, tiredness, poor appetite, weight loss, and changes in skin color. This is caused by changes in the body's hormone system, and may require that the drug be stopped.

Possible side effects

You will probably not have most of the following side effects, but if you have any talk to your doctor or nurse. They can help you understand the side effects and cope with them.


  • low white blood cell count with increased risk of infection*
  • low platelet count with increased risk of bleeding*
  • low red blood cell count (anemia) which may cause tiredness, headache, dizziness*
  • hair loss or thinning, including face and body hair (usually grows back after treatment)
  • long-term or short-term infertility (inability to have children) in men and women

Less common

  • tiredness (fatigue)*
  • sores in mouth or on lips*
  • fever*
  • nausea*
  • vomiting*
  • rash
  • loss of appetite*
  • diarrhea
  • serious infection due to low white blood cell count


  • abnormal blood tests results which suggest that the drug is affecting the liver (Your doctor will discuss the importance of this finding, if any.)
  • allergic reaction with hives, itching, headache, coughing, shortness of breath, or swelling of the face, tongue, or throat*
  • scarring of lung tissue, with cough, difficulty breathing, and shortness of breath that may occur after prolonged use, or even months or years after stopping the drug*
  • leukemia (several years after treatment)*
  • darkened skin
  • heart problems with high-dose treatment, most often in people with thalassemia (a type of genetic anemia that is present at birth)
  • problems with the hormone system that cause weakness, tiredness, poor appetite, weight loss, and darker skin*
  • death due lung damage, bone marrow shutdown, sepsis (severe infection) or other causes

*See "Precautions section" for more detailed information.

There are other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved before 1984 (FDA cannot verify dates of drugs approved before 1984.)

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.

Last Medical Review: 01/12/2010
Last Revised: 07/20/2011