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Rituximab (Mabthera)

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This page tells you about the biological therapy rituximab and its possible side effects. There is information about


What rituximab is

Rituximab (pronounced rit-ux-i-mab) is a monoclonal antibody, which is a type of biological therapy. Rituximab is also known by its brand name, Mabthera. It is a treatment for chronic lymphocytic leukaemia and some types of non Hodgkin lymphoma. Rituximab is also used for some non cancer related illnesses.

Rituximab targets a protein called CD20 on the surface of the leukaemia and lymphoma cells. The antibody sticks to all the CD20 proteins it finds. Then the cells of the immune system pick out the marked cells and kill them.


How you have rituximab

You have rituximab through a drip into a vein (infusion). You have the first treatment in hospital, over a few hours. You may have to stay in hospital overnight because some people have a reaction to it. If you don’t have problems, you can have later treatments as an outpatient. Some people may also change to have it as an injection under the skin

For non Hodgkin lymphoma, you usually have initial treatment with rituximab once a week for 4 weeks. If you have the rituximab in combination with other medicines you may have treatment every 3 weeks. Rituximab is often given with CHOP chemotherapy to make R-CHOP. You usually have 8 of the treatments, so the treatment lasts 6 months. 

If the initial treatment works well, you may then go on to have further rituximab treatment as maintenance therapy. You have this treatment every 2 or 3 months for 2 years.

For chronic lymphocytic leukaemia you usually have rituximab treatment alongside chemotherapy once a month for 6 months.

The side effects associated with rituximab are listed below. If you have rituximab in combination with other treatments the side effects may be different. There is information about rituximab in combination with other cancer drugs in our cancer drugs section.


Common side effects

More than 10 in every 100 people have one or more of the side effects listed below.

  • An increased risk of getting an infection from a drop in white blood cells – it is harder to fight infections and you can become very ill. You may have headaches, aching muscles, a cough, a sore throat, pain passing urine, or you may feel cold and shivery. If you have a severe infection this can be life threatening. Contact your treatment centre straight away if you have any of these effects or if your temperature goes above 38°C. You will have regular blood tests to check your blood cell levels
  • Tiredness and breathlessness due to a drop in red blood cells (anaemia) – you may need a blood transfusion
  • Bruising easily due to a drop in platelets – you may have nosebleeds, bleeding gums after brushing your teeth, or lots of tiny red spots or bruises on your arms or legs (known as petechia)
  • A reaction to rituximab during the infusion, causing flu like symptoms such as a fever, chills and shivering (rigors), a headache and feeling sick – your doctor will give you medicines beforehand to try to prevent a reaction. If you do have a reaction, your nurse will slow or stop your drip for a while
  • Feeling or being sick affects 1 in 5 people (20%), but is usually well controlled with anti sickness medicines
  • A skin rash which may be itchy
  • Low blood pressure in about 1 in 10 people (10%) and more rarely, raised blood pressure
  • Night sweats in about 3 in 20 people (15%)
  • Stomach pain
  • Feeling weak in about 1 in 4 people (25%)
  • A runny nose (rhinitis) – this is usually mild and goes away within an hour of the infusion
  • Loss of fertility – after rituximab treatment you may not be able to become pregnant or father a child. Talk to your doctor before starting treatment if you plan to have a baby in the future. Men may be able to store sperm before starting the treatment

Occasional side effects

Between 1 and 10 in every 100 people have one or more of these.

  • A cough and breathlessness – the rituximab can cause irritation of the lungs. Tell your doctor or nurse if this continues
  • A mild effect on the liver, which does not cause symptoms and will almost certainly go back to normal when the treatment is finished – you will have regular blood tests to keep an eye on how your liver is working
  • Loss of appetite and weight loss
  • Indigestion
  • Dizziness
  • Diarrhoea is usually mild but tell your doctor or nurse, as you can have medicines to control it
  • About 1 in 20 people (5%) have a sudden feeling of warmth and reddening of the face during the infusion – tell your nurse straight away if this happens to you
  • Higher level of sugar in the blood – you may have blood tests to check for this
  • Numbness or tingling in the fingers and toes – you may have trouble with fiddly tasks such as doing up buttons. This can start a few days or weeks after treatment and usually goes away within a few months of the treatment finishing
  • Difficulty sleeping
  • Dizziness
  • Anxiety
  • Red, sore eyes or watery eyes
  • A ringing sound in the ears (tinnitus)
  • Changes in heart rate, which are usually temporary but for a small number of people may be permanent – your doctor will check your heart before and after your treatment
  • Soreness or pain in the muscles or joints

Rare side effects

Fewer than 1 in 100 people have these.

  • Damage to the kidneys caused by chemicals from the dying cancer cells collecting in the blood (tumour lysis syndrome) – you will have regular blood tests to check the chemical balance of your blood and may be given tablets
  • About 1 in 20 people (5%) have a severe allergic reaction, with wheezing, an itchy rash and a drop in blood pressure – your doctor or nurse will give you medicines beforehand to try to prevent a reaction and if you do have a reaction, your nurse will slow or stop your drip for a while
  • Sadness or depression
  • Taste changes
  • A viral infection that damages areas of brain tissue – it can cause confusion, difficulty thinking, memory loss, eyesight changes, weakness, loss of control or sensation in an arm or leg, difficulty walking, or loss of balance. This condition can be very serious and even life threatening. Let your doctor or nurse know straight away if you have any of these changes. Your family or carers should also look out for them. The changes are called progressive multifocal leukoencephalopathy (PML)



Important points to remember

The side effects above may be mild or more severe. A side effect may get better or worse through your course of treatment, or more side effects may develop as the course goes on. This depends on

  • How many times you've had the drug before
  • Your general health
  • The amount of the drug you have (the dose)
  • Other drugs you are having

Coping with side effects

Talk to your doctor, pharmacist or nurse about all your side effects so they can help you manage them. They can give you advice or reassure you. Your nurse will give you a contact number to ring if you have any questions or problems. If in doubt, call them.

Other medicines

Tell your doctor about any other medicines you are taking, including vitamins, herbal supplements and any over the counter remedies. Some drugs can react together.

Hepatitis and rituximab

Hepatitis means inflammation (swelling) of the liver. It can be due to a viral infection or because the liver comes into contact with harmful substances such as alcohol. Rituximab can make hepatitis infection active again. So you should let your doctor know if you have had hepatitis in the past. Your doctor or nurse will do tests to check whether you currently have hepatitis. They call this hepatitis screening.

People with active hepatitis B infection should not have rituximab treatment. People with other types of hepatitis need to see a liver disease expert before starting treatment. The doctor advises on how to prevent damage to the liver during treatment.

Pregnancy and contraception

Rituximab could harm a developing baby, so talk about contraception to your doctor or nurse before having treatment. You need to use reliable contraception during treatment with rituximab and for a year afterwards. 


Breastfeeding is not advisable during this treatment because the drug may come through in the breast milk.



You should not have immunisations with live vaccines while you are having treatment or for at least 6 months afterwards. In the UK, these include rubella, mumps, measles (usually given together as MMR), BCG, yellow fever and Zostavax (shingles vaccine).

You can have other vaccines, but they may not give you as much protection as usual until your immune system has fully recovered from your treatment. It is safe to have the flu vaccine.

It is safe for you to be in contact with other people who've had live vaccines as injections. There can be problems with vaccines you take by mouth (oral vaccines), but not many people in the UK have these now. So there is usually no problem in being with any baby or child who has recently had any vaccination in the UK. You might need to make sure that you aren't in contact with anyone who has had oral polio, cholera or typhoid vaccination recently, particularly if you live abroad.


More information on rituximab

This page does not list all the very rare side effects of this treatment that are very unlikely to affect you. For further information look at the Electronic Medicines Compendium website at

If you have a side effect not mentioned here that you think may be due to this treatment you can report it to the Medicines Health and Regulatory Authority (MHRA) at

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Updated: 29 August 2013