Busulfan (Busilvex®, Myleran®)
Busulfan is a chemotherapy drug that may be given in high doses before a stem cell transplant to treat some types of leukaemia and other types of cancer. It may also be given in standard doses to treat other blood-related disorders.
What busulfan looks like
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Busulfan is available as 2mg white tablets and as a white powder that is dissolved to form a colourless liquid for injection.
Busulfan may be given in one of the following ways:
as tablets swallowed whole
as a drip (infusion) through a fine tube into a vein, usually in the back of your hand (cannula)
through a fine, plastic tube inserted under the skin and into a vein near your collarbone (central line)
into a fine tube inserted into a vein in the crook of your arm (PICC line).
When high-dose busulfan is given before a stem cell transplant, it's usually given four times a day, either as an infusion or as tablets, for four days. If it's given as an infusion, each infusion usually takes about two hours.
When busulfan is used to treat other blood-related disorders, the length of treatment depends on a number of factors, including your response to it.
Busulfan may be given alongside other chemotherapy drugs as part of a combination treatment (regimen). Your nurse or doctor will discuss your treatment plan with you.
Before you begin your treatment your doctor will arrange for you to have blood tests. You'll usually be given anti-sickness drugs before and/or during your treatment.
Each person’s reaction to chemotherapy is different. Some people have very few side effects while others may experience more. The side effects described here won't affect everyone who has busulfan and may be different if you're having more than one type of chemotherapy drug.
We have outlined the most common side effects but haven't included those that are very rare and unlikely to affect you. If you notice any effects that are not listed here, discuss them with your doctor, chemotherapy nurse or pharmacist.
Risk of infection
Busulfan will reduce the number of white blood cells, which help fight infection. White blood cells are produced by the bone marrow. If the number of your white blood cells is low you will be more prone to infections. A low white blood cell count is called neutropenia.
Neutropenia can occur 10–30 days after treatment has been given. The number of white blood cells in your blood will then increase steadily and usually return to normal over several weeks.
Contact your doctor or the hospital straight away if:
your temperature goes above 38°C (100.4°F)
you suddenly feel unwell, even with a normal temperature.
You'll have a blood test before having more chemotherapy to make sure that the number of white blood cells has recovered. Occasionally it may be necessary to delay your treatment if the number of blood cells (blood count) is still low.
Bruising or bleeding
Busulfan can reduce the production of platelets, which help the blood to clot. Tell your doctor if you have any unexplained bruising or bleeding, such as nosebleeds, bleeding gums, blood spots or rashes on the skin. You may need to have a platelet transfusion if your platelet count is low.
Busulfan can reduce the number of red blood cells, which carry oxygen around the body. A low red blood cell count is called anaemia. This may make you feel tired and breathless. Tell your doctor or nurse if you have these symptoms. You may need to have a blood transfusion if the number of red blood cells becomes too low.
Busulfan can cause your skin to darken, especially if you are dark skinned. This is because of the excess production of pigment. It may be more noticeable on some areas of skin, such as the creases across the palms of your hands.
Tiredness and feeling weak
Feeling tired is a common side effect of chemotherapy, especially towards the end of treatment and for some weeks after it’s over. It’s important to try to pace yourself and get as much rest as you need. Try to balance this with some gentle exercise, such as short walks, which will help. If tiredness is making you feel sleepy, don’t operate or drive machinery.
Less common side effects
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Raised levels of uric acid in the blood
This can result in a condition called gout, which causes inflammation of the joints. To prevent this, you may be given a drug called allopurinol (Zyloric®), and you may be asked to drink plenty of fluids. While you're having busulfan, you may have regular blood tests to check your uric acid levels.
Changes to the lungs
The chemotherapy may cause some changes to the lungs. Tell your doctor if you smoke or if you notice any coughing or breathlessness.
High-dose busulfan treatment may irritate the bladder. It’s important to drink as much fluid as you can (at least two litres a day) during the treatment. You may also be given fluids through a drip (infusion) to help prevent bladder irritation. Let your doctor know if you have any discomfort when you pass urine or if you notice any blood in it.
A skin rash can sometimes occur while you're having treatment with busulfan. It’s important to let your doctor know if this happens. Your doctor can prescribe medicine to help with this.
Hair loss doesn't usually happen with standard-dose treatment but it can happen with high-dose treatment.
If you have high-dose treatment, the hair loss is almost always temporary and your hair will grow back once treatment finishes. You may find that your hair grows back straighter, curlier, finer, or a slightly different colour than it was before treatment. Your nurse can give you advice about coping with hair loss.
Treatment with busulfan may cause changes in the way your liver works, although it will return to normal when the treatment finishes. You're very unlikely to notice any problems, but your doctor will take regular blood samples to check your liver is working properly.
Feeling sick (nausea) and being sick (vomiting)
This is a rare side effect unless you're having high doses of busulfan through a vein. You may feel sick a few hours after the treatment is given, and this may last for up to five days. Your doctor can prescribe very effective anti-sickness (anti-emetic) drugs to prevent or greatly reduce nausea and vomiting.
If the sickness isn't controlled, or if it continues, tell your doctor; they can prescribe other anti-sickness drugs which may be more effective. Some anti-sickness drugs can cause constipation. Let your doctor or nurse know if this is a problem.
Your mouth may become sore or dry, or you may notice small ulcers during this treatment. Drinking plenty of fluids, and cleaning your teeth regularly and gently with a soft toothbrush, can help reduce the risk of this happening. Some people may find sucking on ice soothing. Tell your nurse or doctor if you have any of these problems, as they can prescribe mouthwashes and medicine to prevent or clear mouth infections.
You may notice that food tastes different. Normal taste usually comes back after treatment finishes. A dietitian or specialist nurse at your hospital can give you advice about ways of coping with this side effect.
Busulfan can cause diarrhoea. This can usually be easily controlled with medicine, but tell your doctor if it's severe or continues. It's important to drink plenty of fluids if you have diarrhoea.
Loss of appetite
Some people lose their appetite because of chemotherapy treatment. This can be mild and may only last a few days. If it doesn’t improve you can ask to see a dietitian or specialist nurse at your hospital. They can give you advice on improving your appetite and keeping to a healthy weight.
Busulfan can cause confusion. This side effect is very rare and happens only with high-dose treatment. If you notice this side effect, tell your doctor immediately.
Some people may feel dizzy or light-headed. Tell your doctor if you have any of these side effects.
With long-term use of this drug there's a very small risk of developing a second cancer after many years. Your doctor or nurses can discuss this with you.
Cataracts (clouding of the eye's lens)
Rarely, these can occur some years after busulfan treatment. Let your doctor know if you notice any change in your eyesight.
Swelling and tenderness of the breasts may be experienced by both men(gynaecomastia) and women. Your doctor can prescribe medicines or other
treatments to reduce any discomfort.
Fever and chills
These may occur from the time your treatment is given, but they don’t usually last long. Your doctor may prescribe medicines to reduce these effects.
High doses of busulfan (as part of high dose treatment with stem cell support) can very occasionally cause fits. You may be prescribed medication to prevent this happening. Your doctor can discuss this with you.
It’s important to let your doctor know straight away if you feel unwell or have any severe side effects, even if they’re not mentioned above.
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Risk of developing a blood clot
Cancer can increase the risk of developing a blood clot (thrombosis), and chemotherapy may increase this risk further.
A blood clot may cause symptoms such as pain, redness and swelling in a leg, or breathlessness and chest pain. Blood clots can be very serious, so it’s important to tell your doctor straight away if you notice any of these symptoms. Most clots can be treated with drugs that thin the blood. The doctor or nurse can give you more information.
Some medicines, including those that you can buy in a shop or chemist, can be harmful to take when you're having chemotherapy. Tell your doctor about any medicines you're taking, including over-the-counter drugs, complementary therapies and herbal drugs.
Your ability to become pregnant or father a child may be affected by having this treatment. It's important to discuss fertility with your doctor before starting treatment.
It's not advisable to become pregnant or father a child while having busulfan, as it may harm the developing baby. It’s important to use effective contraception while having this drug and for at least a few months afterwards. You can discuss this with your doctor.
It’s not known whether chemotherapy drugs can be present in semen or vaginal fluids. To protect your partner, it’s safest to either avoid sex or use a barrier form of contraception for about 48 hours after chemotherapy.
There's a potential risk that chemotherapy drugs may be present in breast milk. Women are advised not to breastfeed during chemotherapy and for a few months afterwards.
If you’re admitted to hospital for a reason not related to the cancer, it’s important to tell the doctors and nurses looking after you that you're having chemotherapy treatment. You should tell them the name of your cancer specialist so that they can ask for advice.
It’s a good idea to know who you should contact if you have any problems or troublesome side effects when you’re at home. Your chemotherapy nurse or doctor will give you details of who to contact for advice. This should include ‘out-of hours’ contact details if you need to call someone at evenings, overnight or at the weekend.
Things to remember about busulfan tablets
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It’s important to take your tablets at the right times as directed by your doctor.
Swallow your tablets whole with a glass of water.
Always tell any doctors treating you for non-cancerous conditions that you're taking a course of chemotherapy tablets that should not be stopped
or restarted without advice from your cancer specialist.
Keep the tablets in their original packaging, and store them at room temperature away from heat and direct sunlight.
Keep the tablets in a safe place and out of the reach of children.
If your doctor decides to stop the treatment, return any remaining tablets to the pharmacist. Don't flush them down the toilet or throw them away.
If you're sick just after taking the tablets tell your doctor as you may need to take another dose. Don't take another tablet without telling your doctor first.
If you forget to take a tablet, don't take a double dose. Let your doctor know and keep to your regular dose schedule.
This section is based on our Busulfan factsheet which has been compiled using information from a number of reliable sources, including:
Sweetman, et al. Martindale: The Complete Drug Reference. 36th edition. 2009. Pharmaceutical Press.
Electronic Medicines Compendium. (accessed October 2009).
British National Formulary. 58th edition. 2009. British Medical Association and Royal Pharmaceutical Society of Great Britain.
Perry MC. The Chemotherapy Source Book. 4th edition. 2007. Lippincott Williams and Wilkins.