Possible side effects of chemotherapy for CLL

Chemotherapy treatment can cause different side effects. These vary depending on the drugs you have. Your doctor or nurse will tell you which ones you are more likely to get.

Some side effects are more common than others but you won’t have them all. They can usually be reduced and controlled with drugs. Your doctor or nurse can tell you how to manage them. The most frequent ones include:

  • increased risk of infection
  • anaemia (reduced number of red blood cells)
  • bruising and bleeding (reduced number of blood clotting cells)
  • feeling sick or vomiting
  • hair loss of thinning
  • mouth ulcers
  • tiredness.

Most side effects are short term and will improve gradually when the treatment is over.

One of the most common side effects is an increased risk of infection. Always contact the hospital and speak to a nurse or doctor if:

  • you have a temperature
  • you suddenly feel unwell
  • you have any symptoms of an infection – a cold, sore throat, cough, passing urine frequently (urine infection), diarrhoea, feeling shivery and shaking etc.

Chemotherapy side effects

If you’re taking a single chemotherapy drug, such as chlorambucil, any side effects you have will usually be mild. Treatment with a combination of two or more chemotherapy drugs may cause more side effects.

Risk of infection

This treatment can reduce the number of white blood cells in your blood. These cells fight infection. If the number of white blood cells is low, you are more likely to get an infection. A low white blood cell count is called neutropenia.

If you have an infection, it is important to treat it as soon as possible. Contact the hospital straight away on the 24-hour contact number you have if:

  • your temperature goes over 37.5°C (99.5F)
  • you suddenly feel unwell, even with a normal temperature
  • you have symptoms of an infection.

Symptoms of an infection include:

  • feeling shivery
  • a sore throat
  • a cough
  • diarrhoea
  • needing to pass urine often.

It is important to follow any specific advice your cancer treatment team gives you.

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

Anaemia (reduced number of red blood cells)

Chemotherapy may reduce the number of red blood cells (haemoglobin) in your blood. A low level of red blood cells is known as anaemia, which can make you feel very tired and lethargic. You may also become breathless.

Increased bruising and bleeding

Chemotherapy can reduce the number of platelets in your blood. Platelets are cells that help the blood to clot. If you develop any unexplained bruising or bleeding such as nosebleeds, bleeding gums, blood spots or rashes on the skin, contact your doctor or the hospital straight away.

If your red blood cells or platelets take a while to recover, you may need a blood transfusion or a platelet transfusion. You can have transfusions as an outpatient.

Anyone treated with fludarabine or bendamustine should only be given blood and platelet transfusions that have been treated with radiation (irradiated). Irradiated transfusions should always be used during and after you’ve finished your treatment. This lowers the risk of the donated blood cells reacting against your own. Your hospital team should give you a card to carry or a MedicAlert ID tag to wear, so that the hospital staff are aware in case of an emergency.

Feeling sick (nausea)

Some chemotherapy drugs can make you feel sick (nauseated) or possibly be sick (vomit). Your haematologist will prescribe anti-sickness (anti-emetic) drugs to prevent this. Let your doctor or nurse know if your anti-sickness drugs are not helping, as there are several different types you can try.

Sore mouth

Your mouth may become sore (or dry), or you may notice small ulcers during treatment. Some people find that sucking on ice may be soothing.

Drinking plenty of fluids, and cleaning your teeth regularly and gently with a soft toothbrush, can help to reduce the risk of this happening. 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.

Tiredness (fatigue)

You are likely to become more tired as treatment goes on and you will have to take things slowly. Try to pace yourself and save your energy for things that you want to do or that need doing. Balance rest with some physical activity – even going for short walks will help you to feel less tired. We have more information about fatigue that may help. 

Hair loss

Some chemotherapy drugs may cause hair loss. Some people may have complete hair loss including eyelashes and eyebrows. Others may only experience partial hair loss or thinning. It depends on what chemotherapy drugs you are having (your doctor or nurse can tell you more about what to expect).

If you do have hair loss, your hair should start to grow back within about 3–6 months of the end of treatment. It may grow back straighter, curlier, finer, or a slightly different colour than it was before. Your nurse can give you advice about coping with hair loss and how to look after your scalp.

Most drugs used to treat CLL do not cause hair loss.


Men who may possibly father a child, or women who might become pregnant, should use effective contraception during their course of chemotherapy treatment. This is because the drugs might harm a baby conceived during this time. It is important to carry on using effective contraception after your treatment finishes, for up to a year afterwards. You can discuss this with your doctor or specialist nurse.

A barrier contraception such as a condom should be used during sex within the first 48 hours after chemotherapy, to protect your partner from any of the drug that may be present in semen or vaginal fluid. You can discuss this with your doctor.


Some of the drugs used to treat CLL may cause infertility (being unable to become pregnant or to father a child). This may be temporary or permanent.

If you think that you may want to have children in the future, talk to your doctors about this before starting chemotherapy treatment. They will be able to tell you whether your fertility is likely to be affected.

If you have a partner, it’s a good idea for both of you to be there during these discussions. You can then make an informed decision about your options.

If you have high-dose chemotherapy or radiotherapy before a stem cell transplant or bone marrow transplant, you are likely to become permanently infertile. Men may be able to have sperm stored before they start treatment (sperm banking) and sometimes women may be able to have eggs collected and frozen. It’s important to speak to your medical team about this before your treatment begins.

Back to Side effects of chemotherapy for CLL

Possible effects on fertility

Chemotherapy can affect your fertility. If this is a concern for you, it’s very important to discuss it with your doctor before treatment.