Generic Name: busulfan (byoo-SUL-fen)
Trade Name: Myleran®, Busulfex®
For which condition is Busulfex indicated? Busulfan is used in combination with with cyclophosphamide or fludarabine/clofarabine as a conditioning agent prior to bone marrow transplantation, especially in chronic myelogenous leukemia (CML). It is also approved for the treatment of advanced acute myeloid leukemia (AML) and other certain blood disorders like polycythemia vera and myeloid metaplasia.
What is the mechanism of action? Busulfan belongs to a group of drugs called alkylating agents. Busulfan produces its anti-cancer effects by causing a chemical reaction that damages the DNA in a cell. The DNA damage caused by busulfan results in cellular death.
How is busulfan typically given (administered)? Busulfan can be given either intravenously (into a vein) or as a tablet orally and the dose depends on several factors, including the condition being treated, the size of the patient, the particular regimen being used and the overall health of the patient. Once the drug is given, it is ultimately cleared from the body through the kidneys.
How are patients typically monitored? Patients will usually have scheduled meetings with their healthcare provider while they are being treated with busulfan. Typically, blood will be drawn to check levels of blood cells and to monitor functions of some organ systems, such as the kidneys or liver. In certain situations where higher doses of busulfan are administered, the blood busulfan level will be carefully monitored. Side effects are known to occur frequently when blood busulfan reaches certain levels. Patients may also undergo physical examinations, scans or other measures to assess side effects and response to therapy. Due to some uncommon, yet serious side effects of treatment with busulfan, patients’ monitoring may include examination of the heart, liver, and lungs.
A condition referred to as “busulfan lung”, which is associated with cough, low-grade fever and difficulty breathing, may occur between 8 months and 10 years following therapy. If patients experience any of these symptoms, they should contact their healthcare provider. In addition, a heart abnormality, referred to as cardiac tamponade, uncommonly occurs in patients treated with busulfan. Patients experiencing abdominal pain and vomiting should contact their healthcare provider, as these symptoms tend to precede the diagnosis of cardiac tamponade.
Patients will undergo monitoring of liver function, as a condition referred to as hepatic veno-occlusive disease may occur. Patients with yellowing of the skin or eyes, or abdominal swelling should contact their healthcare provider. A reduction in the body’s production of steroids may also be a side effect of treatment with busulfan. Levels of these steroids may be measured, and patients should contact their healthcare provider if they are experiencing fatigue, loss of appetite, vomiting, diarrhea, weakness, dizziness and nausea, as these may be indicative of low levels of adrenal steroids.
What are the common (occur in 30% or more of patients) side effects of treatment with busulfan?
- Low white blood cell levels – increases risk of infection
- Low red blood cell levels – increases risk of anemia and blood transfusions
- Low platelet levels – increases risk of bleeding
- Nausea and vomiting
- Loss of appetite
- Mouth sores
What are the less common (occur in 10% to 29% of patients) side effects of treatment with busulfan?
- Discoloration of skin
- Hair loss
- Insomnia, dizziness, anxiety, depression
- Seizures (usually associated with high dose therapy)
This is not a complete list of side effects. Some patients may experience other side effects that are not listed here. Patients may wish to discuss with their physician the other less common side effects of this drug, some of which may be serious.
Some side effects may require medical attention. Other side effects do not require medical attention and may go away during treatment. Patients should check with their physician about any side effects that continue or are bothersome.
What are the possible late side effects of treatment with busulfan? With the use of busulfan, there is a risk of developing side effects months or years after treatment has been completed. In uncommon instances, a second cancer may occur as a result of receiving this drug. A secondary malignancy is a new cancer that is unrelated the cancer that was initially treated. Secondary malignancies occur as a result of previous treatment with radiation or chemotherapy. A second uncommon side effect, referred to as “busulfan lung” may also occur from treatment with this agent. Patients experiencing difficulty breathing, cough or low-grade fever should contact their physician. Patients should discuss these late side effects with their physician.
What can patients do to help alleviate or prevent discomfort and side effects?
- Pay careful attention to the physician’s instructions and inform the physician of any side effects.
- Maintain adequate rest and nutrition.
- If possible, avoid large crowds or persons who are sick or not feeling well, as busulfan may leave patients susceptible to infection.
- Wash your hands often to reduce the risk of infection.
- Avoid activities that may cause injury or bruising.
- Use a soft toothbrush and an electric razor to prevent cuts on the mouth or skin.
- For mouth sores, patients should rinse their mouths three times a day with a salt and soda solution (8oz of water mixed with ½ to 1 tsp of baking soda and/or ½ to 1 tsp of salt) and brush their teeth with a soft toothbrush to help prevent development of mouth sores.
- Drink plenty of fluids. (Patients should ask their physician about the amount of liquid to consume during a day.)
- Eat small meals frequently to help alleviate nausea.
- Taking busulfan on an empty stomach may help prevent nausea and vomiting.
Are there any special precautions patients should be aware of before starting treatment?
- Patients should inform their physician if they are pregnant, breastfeeding or planning a family in the near future. This drug may cause birth defects. It is important to use some kind of birth control while undergoing treatment. Also, patients may want to talk to their physician if they are considering having children in the future, since some drugs may cause fertility problems.
- It is important that patients inform their physician of any pre-existing conditions (chicken pox, heart disease, kidney disease, liver disease, lung disease, etc.) as they may worsen with this drug.
- Patients should inform their physician if they have a history of seizures or gout.
- Patients should inform their physician of any other medication they are taking (whether prescription or over-the-counter, including vitamins, herbs, etc.) as they may interfere with treatment.
- Patients should check with their physician before starting any new drug or nutritional supplement.
- Patients should inform their physician of any known drug or food allergies or any reactions to medications they have experienced in the past.
- If an oral dose is missed, do not double up on doses. Patients should contact their physician in this event.
- Keep tablets out of reach of children and return to the pharmacy for safe disposal if treatment is terminated.
When should patients notify their physician?
- Difficulty breathing, shortness of breath, congestion
- Yellowing of skin or eyes
- Abdominal pain with vomiting
- Signs of infection: redness, pus, swelling
- Signs of a cold or flu: sore throat, chills, etc.
- Unexplained bleeding: nosebleeds, bruising, tarry black stools, blood in the urine
- Prolonged diarrhea
- Prolonged nausea and/or vomiting
- Sores in the mouth
- Painful, burning or frequent urination, dark urine
- Abdominal swelling
- Extreme, prolonged fatigue
- Pain in side, joint pain
- Numbness or tingling of extremities
- Chest pain, palpitations
- Signs of busulfan lung: cough, low-grade fever, difficulty breathing
- Signs of cardiac tamponade: abdominal pain and vomiting
- Signs of hormone deficiencies: fatigue, loss of appetite, vomiting, diarrhea, weakness, dizziness and nausea
What is a package insert?
A package insert is required by the FDA and contains a summary of the essential scientific information needed for the safe and effective use of the drug for healthcare providers and consumers. A package insert typically includes information regarding specific indications, administration schedules, dosing, side effects, contraindications, results from some clinical trials, chemical structure, pharmacokinetics and metabolism of the specific drug. By carefully reviewing the package insert, you will get the most complete and current information about how to safely use this drug. If you do not have the package insert for the drug you are using, your pharmacist or physician may be able to provide you with a copy.
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