Treosulfan is a chemotherapy drug used to treat used to treat cancer of the ovary. It may also be used to treat other cancers.

It is best to read this information with our general information about chemotherapy and the type of cancer you have.

Treosulfan is usually given into a vein or as tablets. You usually have it as an outpatient. Your cancer doctor or nurse will tell you how often you will have it.

Like all chemotherapy drugs, treosulfan can cause side effects. Some of the side effects can be serious, so it is important to read the detailed information below.

Your healthcare team can give you advice on how to manage any side effects. Tell your doctor or nurse straight away if you:

  • have a temperature
  • feel unwell
  • have severe side effects, including any we do not mention here.

Rarely, side effects may be life-threatening. Your cancer doctor or nurse can explain the risk of these side effects to you.

If you need medical attention for any reason other than cancer, always tell the healthcare staff that you are having this treatment.

What is treosulfan?

Treosulfan is a chemotherapy drug used to treat ovarian cancer. It is sometimes given with other chemotherapy drugs. It may be used to treat other cancers as part of a clinical trial.

This information is best when read with our general information about chemotherapy and your type of cancer.

How treosulfan is given

You will usually have treosulfan in the chemotherapy day unit. A chemotherapy nurse will give it to you.

During treatment you usually see a cancer doctor, a chemotherapy nurse or a specialist nurse. This is who we mean when we mention doctor or nurse in this information.

Before or on the day of treatment, a nurse or person trained to take blood (phlebotomist) will take a blood sample from you. This is to check that it is okay for you to have chemotherapy.

You will also see a doctor or nurse before you have chemotherapy. They will ask you about how you have been. If your blood results are all right on the day of your treatment, the pharmacist will prepare your chemotherapy. Your nurse will tell you when your treatment is likely to be ready.

Treosulfan can be given as an injection into a vein or as capsules by mouth.

Having treosulfan by injection

Your nurse gives you anti-sickness (anti-emetic) drugs and sometimes a steroid as an injection into a vein. They give you the drugs and chemotherapy through one of the following:

  • a short thin tube that the nurse puts into a vein in your arm or hand (cannula)
  • a fine tube that goes under the skin of your chest and into a vein close by (central line)
  • a fine tube that is put into a vein in your arm and goes up into a vein in your chest (PICC line).

Your nurse gives you treosulfan as a drip (infusion) into your cannula or line every 1–3 weeks.

When the chemotherapy is being given

Some people might have side effects while they are having the chemotherapy:

Allergic reaction

Rarely, treosulfan may cause an allergic reaction while it’s being given. Your nurse will check you for this. If you have a reaction, they will treat it quickly.

You’ll be monitored closely during treatment, but tell your nurse or doctor if you feel unwell or have any of the following symptoms:

  • a rash
  • feeling itchy, flushed or short of breath
  • swelling of your face or lips
  • feeling dizzy
  • having pain in your tummy, back or chest
  • feeling unwell.

The drug leaks outside the vein

If this happens when you’re having treosulfan, it can damage the tissue around the vein. This is called extravasation. Tell the nurse straight away if you have any stinging, pain, redness or swelling around the vein.

Extravasation is not common. But if it happens, it’s important that it’s dealt with quickly.

If you get any of these symptoms after you get home, contact the doctor or nurse straight away on the number they gave you.

Taking treosulfan capsules

Before you leave hospital, the nurse or pharmacist will give you treosulfan capsules to take at home. Always take your capsules exactly as explained. This is important to make sure they work as well as possible for you. Always swallow them whole with a glass of water.

If you are sick just after taking the capsules, contact the hospital. You may need to take another dose. If you forget to take a capsule, do not take a double dose. Keep to your regular schedule and let your doctor or nurse know.

There are other important things to remember about your capsules:

  • Keep them in the original package at room temperature away from heat and direct sunlight.
  • Keep them safe and out of the reach of children.
  • Return any remaining capsules to the pharmacist if your treatment is stopped.

Your course of chemotherapy

You have chemotherapy as a course of several sessions (cycles) of treatment over a few months. Your doctor or nurse will tell you more about this and the number of cycles you are likely to have.

Going home

Before you go home, the nurse or pharmacist will give you anti-sickness (anti-emetic) drugs to take. Take all your tablets exactly as you’ve been told.

Possible side effects of treosulfan

We explain the most common side effects of treosulfan here. But we don’t include all the rare ones that are unlikely to affect you.

You may get some of the side effects we mention, but you are very unlikely to get all of them. If you are having other chemotherapy drugs as well, you may have some side effects that we don’t list here. Always tell your doctor or nurse about the side effects you have.

Your doctor can prescribe drugs to help control some side effects. It is very important to take them exactly as your nurse or pharmacist has explained. This means they will be more likely to work better for you. Your nurse will give you advice about managing your side effects.

After your treatment is over, the side effects will start to improve.

Serious and life-threatening side effects

Sometimes cancer drugs can result in very serious side effects, which rarely may be life-threatening. Your cancer doctor and nurse can explain the risk of these side effects to you.

Contact the hospital

Your nurse will give you telephone numbers to call the hospital if you feel unwell or need advice any time of day or night. Save these numbers in your mobile phone or keep them somewhere safe.

More information about this drug

We’re not able to list every side effect for this treatment here, particularly the rarer ones. For more detailed information you can visit the electronic Medicines Compendium (eMC).

Risk of infection

Treosulfan can reduce the number of white blood cells in your blood. This will make you more likely to get an infection. When the number of white blood cells is low, it’s called neutropenia.

Your nurse can tell you when your white blood cells are likely to be at their lowest. Contact the hospital straight away on the contact number you’ve been given if:

  • your temperature goes over 37.5°C (99.5°F) or over 38°C (100.4°F), depending on the advice given by your chemotherapy team
  • you suddenly feel unwell, even with a normal temperature
  • you have symptoms of an infection – this can include feeling shaky, a sore throat, a cough or needing to pass urine often.

The number of white blood cells usually increases steadily and returns to normal before your next chemotherapy. You will have a blood test before having more chemotherapy. If your number of white blood cells is still low, your doctor may delay your treatment for a short time.

Bruising and bleeding

Treosulfan can reduce the number of platelets in your blood. Platelets are cells that help the blood to clot. Tell your doctor if you have any bruising or bleeding you can’t explain. This includes nosebleeds, bleeding gums, blood spots or rashes on the skin. Some people may need a drip to give them extra platelets.

Anaemia (low number of red blood cells)

Treosulfan can reduce the number of red blood cells in your blood. These cells carry oxygen around the body. If the number of red blood cells is low, you may be tired and breathless. Tell your doctor or nurse if you feel like this.

If you are very anaemic, you may need a drip to give you extra red blood cells (blood transfusion).

Feeling sick

You may feel sick after chemotherapy. Your doctor will prescribe anti-sickness (anti-emetic) drugs to help prevent or control sickness. Take the drugs exactly as your nurse or pharmacist explains to you. It’s easier to prevent sickness than to treat it after it has started.

If you still feel sick or are vomiting, contact the hospital as soon as possible. They can give you advice and change the anti-sickness drug to one that works better for you.

Hair loss

You’re unlikely to lose all the hair from your head, but your hair may thin. This usually starts after your first or second cycle of chemotherapy. It is almost always temporary and your hair will grow back after chemotherapy ends. Your nurse can give you advice about coping with hair loss.


Feeling very tired is a common side effect. It’s often worse towards the end of treatment and for some weeks after it’s finished. Try to pace yourself and get as much rest as you need. It helps to balance this with some gentle exercise, such as short walks. If you feel sleepy, don’t drive or operate machinery.

Skin changes

During treatment and for several months afterwards, you'll be more sensitive to the sun and your skin may burn more easily than usual. You can still go out in the sun, but use a suncream with a sun protection factor (SPF) of at least 30, and cover up with clothing and a hat.

Bladder irritation

Treosulfan may irritate your bladder and cause discomfort when you pass urine. Make sure you drink plenty of fluids during the 24 hours following chemotherapy. Try to drink at least two litres (three and a half pints).

It is also important to empty your bladder regularly and to try to pass urine as soon as you feel the need to go.

Less common side effects of treosulfan

Lung problems

Treosulfan can cause changes to the lungs. Always tell your doctor if you develop wheezing, a cough, a fever or feel breathless.

You should also let them know if any existing breathing problems get worse. They can arrange for you to have tests to check your lungs.

Second cancer

Rarely, treosulfan can increase the risk of developing a second cancer. The second cancer is usually leukaemia.

But the benefits of treatment usually far outweigh this risk. Your doctor can talk to you about this.

Other information about treosulfan

Blood clot risk

Cancer increases the chances of a blood clot (thrombosis) and chemotherapy can add to this.

A clot can cause symptoms such as pain, redness and swelling in a leg, breathlessness and chest pain. Contact your doctor straight away if you have any of these symptoms.

A blood clot is serious, but your doctor can treat it with drugs that thin the blood. Your doctor or nurse can give you more information.

Other medicines

Some medicines can interact with or be harmful when you are having chemotherapy. This includes medicines you can buy in a shop or chemist. Tell your doctor about any medicines you are taking, including over-the-counter drugs, complementary therapies and herbal drugs.

People having treosulfan should not have live vaccines. Your nurse or doctor can give you more information about this.


Treosulfan can affect your fertility (being able to get pregnant or father a child). If you are worried about this, you can talk to your doctor before treatment starts.


Your doctor will advise you not to become pregnant or father a child during treatment. This is because the drugs may harm a developing baby. It’s important to use contraception during and for a few months after chemotherapy. You can talk to your doctor or nurse about this. 


If you have sex within the first couple of days of having chemotherapy, you need to use a condom. This is to protect your partner in case there is any chemotherapy in your semen or vaginal fluid.


Women are advised not to breastfeed during treatment and for a few months after. This is in case there is chemotherapy in their breast milk.

Medical and dental treatment

If you need to go into hospital for any reason other than cancer, always tell the doctors and nurses that you are having chemotherapy. Give them the contact details for your cancer doctor.

Talk to your cancer doctor or nurse if you think you need dental treatment. Always tell your dentist you are having chemotherapy.