Busulfan is used to treat chronic myelogenous leukemia (CML). It does not cure the disease but helps to control it so that your quality of life is improved.

This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.

This drug may also be used as a pretreatment for patients who are undergoing stem cell transplant.

Take this medication by mouth with or without food as directed by your doctor, usually once daily.

The dosage is based on your weight, medical condition, lab tests, and response to treatment. Your treatment may be stopped for a short time if your blood counts are too low. Keep all medical and lab appointments.

Do not increase your dose or take this medication more often than prescribed. Your condition will not improve any faster, and the risk of serious side effects may be increased.

Since this drug can be absorbed through the skin and lungs, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets.

Tell your doctor if your condition does not get better or if it gets worse.

See also Warning section.

Darkening skin or dry mouth may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Many people using this medication may have serious side effects. However, you have been prescribed this drug because your doctor has judged that the benefit to you is greater than the risk of side effects. Careful monitoring by your doctor may decrease your risk.

Tell your doctor right away if you have any serious side effects, including:

• signs of liver disease (such as nausea/vomiting that doesn't stop, severe stomach/abdominal pain, yellowing skin/eyes, dark urine)
• seizures
• unusual/extreme tiredness
• painful urination
• toe/joint pain
• fainting
• fast/pounding heartbeat
• cloudy/blurred vision

Busulfan has rarely caused very serious (possibly fatal) lung disease. This may occur after months to years of using busulfan. Tell your doctor right away if you develop symptoms of lung disease, including cough that doesn't go away, chest pain, shortness of breath.

Busulfan may cause other cancers (such as acute leukemia, tumors). Consult your doctor for more details. Tell your doctor right away if you notice any symptoms of cancer, including unusual lumps, sudden weight loss.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking busulfan, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• blood/bone marrow disorders (such as bone marrow suppression, neutropenia, thrombocytopenia, anemia)
• brain disorders (such as seizures, head injury)

Busulfan can make you more likely to get infections or may make current infections worse. Stay away from anyone who has an infection that may easily spread (such as chickenpox, COVID-19, measles, flu). Talk to your doctor if you have been exposed to an infection or for more details.

Tell your health care professional that you are using busulfan before having any immunizations/vaccinations. Avoid contact with people who have recently received live vaccines (such as flu vaccine inhaled through the nose).

To lower the chance of getting cut, bruised, or injured, use caution with sharp objects like razors and nail cutters, and avoid activities such as contact sports.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

In female children, this medication may prevent puberty. Contact the doctor for more information.

This medication can affect fertility in both males and females. Ask your doctor for more details.

Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using busulfan. Busulfan may harm an unborn baby. Women using this medication should ask about reliable forms of birth control during treatment and for at least 6 months after the last dose. Men using this medication should ask about reliable forms of birth control during treatment and for at least 3 months after the last dose. If you or your partner becomes pregnant, talk to your doctor right away about the risks and benefits of this medication.

It is unknown if this drug passes into breast milk. Because of the possible risk to the infant, breastfeeding is not recommended while using this drug. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669. Symptoms of overdose include: easy bruising/bleeding, pale skin, unusual tiredness.

Do not share this medication with others.

Lab and/or medical tests (such as complete blood count, hematocrit/hemoglobin, liver function) must be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).