Rituximab is a targeted cancer drug. It is a treatment for certain types of lymphoma or leukaemia. 

You might have the original rituximab drug called Mabthera. Or a biosimilar such as Truxima, Ruxience or Rixathon.

A biosimilar is a very similar copy of the original drug, but it is not exactly the same. Biosimilars undergo strict testing to check they work just as well as the original drug.

How does rituximab work?

Rituximab is a type of targeted cancer drug called a monoclonal antibody. Monoclonal antibodies target proteins on the surface of cancer cells. Rituximab targets a protein called CD20. CD20 is found on white blood cells called B cells.  

Rituximab works by attaching itself to all the CD20 proteins it finds. Then the cells of the immune system Open a glossary item pick out the marked cells and kill them.

How do you have rituximab ?

You might have rituximab on its own or with other cancer drugs (as part of a treatment regimen). You usually have it as a drip into your bloodstream (intravenously). Or as an injection under the skin (subcutaneously).

Drugs into your bloodstream

You might have treatment through a long plastic tube that goes into a large vein in your chest. The tube stays in place throughout the course of treatment. This can be a:

  • central line
  • PICC line
  • portacath

If you don't have a central line

You might have treatment through a thin short tube (a cannula) that goes into a vein in your arm. You have a new cannula each time you have treatment.

As an injection under your skin

You have injections under the skin (subcutaneous injection) into the stomach.

You might have stinging or a dull ache for a short time after this type of injection but they don't usually hurt much. The skin in the area may go red and itchy for a while.

When do you have rituximab?

You usually have rituximab as cycles of treatment. This means that you have the drug and then a rest to allow your body to recover. Each cycle varies depending on what type of cancer you have.

Rituximab can cause an allergic reaction. So before each dose you have paracetamol, a steroid and an antihistamine drug such as chlorphenamine (Piriton).

For the first cycle of rituximab, you have it as a drip into your bloodstream slowly over a few hours. This is to prevent an allergic reaction. Your nurse will increase how fast it goes in (rate) approximately every 30 minutes if you have no allergic reaction.

Your next rituximab drip will usually go in quicker, but this will depend on how you got on with the first cycle.  

Depending on your cancer type, you may be able to have rituximab as a subcutaneous injection. You can only have rituximab as an injection if you’ve had at least one dose of rituximab into your bloodstream. And you didn't have any serious side effects whilst you had it.

Your healthcare team will explain more about how you will have your treatment.


You have blood tests before and during your treatment. They check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.

Before treatment starts, you have a blood test to check for viruses such as Hepatitis B infection or Cytomegalovirus (CMV) Open a glossary item. This is because infection with these viruses can become active again if you’ve had them in the past. 

What are the side effects of rituximab?

Side effects can vary from person to person. They also depend on what other treatments you're having. 

When to contact your team

Your doctor, nurse or pharmacist will go through the possible side effects. They will monitor you during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:

  • you have severe side effects 

  • your side effects aren’t getting any better

  • your side effects are getting worse

Early treatment can help manage side effects better. 

Contact your advice line immediately if you have signs of infection, including a temperature above 37.5C or below 36C.

We haven't listed all the side effects here. Remember it is very unlikely that you will have all of these side effects. But you might have some of them at the same time.

You usually have rituximab with chemotherapy drugs. The side effects listed below are from having rituximab on its own or in combination with chemotherapy drugs.

Common side effects

These side effects happen in more than 10 in 100 people (more than 10%). You might have one or more of them. They include:

Increased risk of getting an infection 

Increased risk of getting an infection is due to a drop in white blood cells. Symptoms include a change in temperature, aching muscles, headaches, feeling cold and shivery and generally unwell. You might have other symptoms depending on where the infection is.

Infections can sometimes be life threatening. You should contact your advice line urgently if you think you have an infection. 

Bruising and bleeding 

This is due to a drop in the number of platelets in your blood. These blood cells help the blood to clot when we cut ourselves. You may have nosebleeds or bleeding gums after brushing your teeth. Or you may have lots of tiny red spots or bruises on your arms or legs (known as petechiae).

An allergic reaction 

Some people have an allergic reaction to rituximab. This reaction is most likely to happen during treatment and when you first have the treatment. Symptoms of an allergic reaction include high temperature (fever), chills, feeling or being sick and difficulty breathing. 

Your nurse will give you medicines beforehand to try to prevent a reaction. Tell your nurse straight away if you have any symptoms of an allergic reaction. They will slow down or stop your drip for a while.

General swelling

A build up of fluid (oedema) that may cause swelling in your arms, hands, ankles, legs, face and other parts of the body. Contact your doctor if this happens to you.

Feeling or being sick 

Feeling or being sick is usually well controlled with anti sickness medicines. It might help to avoid fatty or fried foods, eat small meals and snacks and take regular sips of water. Relaxation techniques might also help.

It is important to take anti sickness medicines as prescribed even if you don’t feel sick. It is easier to prevent sickness rather than treat it once it has started.

Hair loss 

You could lose all your hair. This includes your eyelashes, eyebrows, underarms, legs and sometimes pubic hair. Your hair will usually grow back once treatment has finished but it is likely to be softer. It may grow back a different colour or be curlier than before. 

Skin changes  

Skin problems include a skin rash, dry skin and itching. Less commonly you might have a raised itchy rash on the skin also known as hives.

Rituximab can also cause a severe skin reaction, but this is rare. Symptoms usually start as tender red patches which leads to peeling or blistering of the skin. You might also feel feverish, and your eyes may be more sensitive to light. This is serious and could be life threatening

Skin problems usually go back to normal when your treatment finishes. Let your doctor, nurse or pharmacist know of any skin changes.


Tell your healthcare team if you keep getting headaches. They can give you painkillers to help.

Tiredness and weakness

You might feel very tired and as though you lack energy.

Various things can help you to reduce tiredness and cope with it, for example exercise. Some research has shown that taking gentle exercise can give you more energy. It is important to balance exercise with resting.

Occasional side effects

These side effects happen in between 1 and 10 out of every 100 people (between 1 and 10%). You might have one or more of them. They include:

  • breathlessness and looking pale due to a drop in red blood cells (anaemia)
  • weight loss
  • high blood sugar levels - symptoms might include feeling very thirsty, a dry mouth, passing urine very often, feeling tired, blurred vision or weight loss
  • low levels of calcium in your blood causing symptoms such as painful muscle spasms and cramps, twitching of muscles, numbness or tingling in feet and hands or around the mouth
  • high levels of a substance (enzyme Open a glossary item) called LDH in the blood. You will have blood tests to check this
  • difficulty falling or staying sleeping (insomnia)
  • dizziness
  • feeling agitated and anxious, rarely rituximab can also make you feel very low in mood or nervous
  • unusual feelings of the skin – such as numbness, tingling, pricking, burning, a creeping skin feeling, or reduced sense of touch
  • heart problems such as an abnormal heart rhythm and a heart attack
  • low blood pressure that can cause you to feel lightheaded or dizzy, sometimes this can happen when you stand up from sitting or lying down (orthostatic hypotension)
  • high blood pressure that might cause headaches, confusion, vision problems or chest pain
  • eye problems such as dry or watery eyes or red, sore, itchy eyes (conjunctivitis)
  • hearing changes such as ringing or buzzing in the ear (tinnitus) and ear pain
  • pain in different parts of your body such as your tummy (abdomen), muscles, joints, back, neck and where the cancer is
  • stiffness in your muscles, arms or legs
  • lung problems such as shortness of breath, tightening in the chest, chest pain or coughing. Rarely you might have asthma or low levels of oxygen
  • constipation
  • diarrhoea
  • difficulty swallowing
  • mouth sores and ulcers
  • indigestion symptoms include heartburn, bloating, and burping
  • loss of appetite
  • a blocked, runny or itchy nose, or sneezing
  • sore throat
  • sweating and, or night sweats
  • generally feeling unwell
  • flushing - sudden reddening and warmth of the neck, upper chest and face
  • several body parts (organs) stopping working

Rare side effects

These side effects happen in fewer than 1 in 100 people (fewer than 1%). You might have one or more of them. They include:

  • changes to the way your blood clots - too little clotting causing bleeding or too much clotting causing blood clots
  • a blood disorder where your red blood cells get destroyed faster than they can be made (haemolytic anaemia)
  • a condition where your bone marrow Open a glossary item stops making your blood cells Open a glossary item (aplastic anaemia)
  • swollen lymph nodes Open a glossary item
  • swollen tummy (abdomen)
  • changes to the levels of chemicals in your body caused by a breakdown of tumour cells (tumour lysis syndrome) - you will have regular blood tests to check for this
  • taste changes
  • inflammation of your blood vessels – symptoms can vary depending on which blood vessels are affected - general symptoms include feeling very tired, loss of appetite, weight loss, a high temperature, and aches and pains
  • a hole in your stomach or bowel (perforation) - contact your doctor straight away if you have pain, sever cramps, feeling tightness or bloating in the stomach area
  • kidneys stopping working - you will have tests to check how well your kidneys work

Coping with side effects

We have more information about side effects and tips on how to cope with them.

What else do I need to know?

Other medicines, foods and drinks 

Cancer drugs can interact with medicines, herbal products, and some food and drinks. We are unable to list all the possible interactions that may happen. An example is grapefruit or grapefruit juice which can increase the side effects of certain drugs.

Tell your healthcare team about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies. Also let them know about any other medical conditions or allergies you may have.

Loss of fertility 

It is not known whether this treatment affects fertility Open a glossary item in people. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.

Pregnancy and contraception 

This treatment may harm a baby developing in the womb. It is important not to become pregnant or get someone pregnant while you are having treatment with this drug and for at least a year afterwards.

Talk to your doctor or nurse about effective contraception before starting treatment. Let them know straight away if you or your partner become pregnant while having treatment.


Don’t breastfeed during this treatment and for 12 months afterwards. The drug may come through in the breast milk.

Treatment for other conditions

If you are having tests or treatment for anything else, always mention your cancer treatment. For example, if you are visiting your dentist.


Don’t have immunisations with live vaccines while you’re having treatment and for up to 12 months afterwards. The length of time depends on the treatment you are having. Ask your doctor or pharmacist how long you should avoid live vaccinations.

In the UK, live vaccines include rubella, mumps, measles, BCG, yellow fever and one of the shingles vaccines called Zostavax.

You can have:

  • other vaccines, but they might not give you as much protection as usual
  • the flu vaccine (as an injection)
  • the coronavirus (COVID-19) vaccine - talk to your doctor or pharmacist about the best time to have it in relation to your cancer treatment

Members of your household who are aged 5 years or over are also able to have the COVID-19 vaccine. This is to help lower your risk of getting COVID-19 while having cancer treatment and until your immune system Open a glossary item recovers from treatment.

Contact with others who have had immunisations - You can be in contact with other people who have had live vaccines as injections. Avoid close contact with people who have recently had live vaccines taken by mouth (oral vaccines) such as the oral typhoid vaccine. Sometimes people who have had the live shingles vaccine can get a shingles type rash. If this happens they should keep the area covered.

If your immune system is severely weakened, you should avoid contact with children who have had the flu vaccine as a nasal spray as this is a live vaccine. This is for 2 weeks following their vaccination.

Babies have the live rotavirus vaccine. The virus is in the baby’s poo for about 2 weeks and could make you ill if your immunity is low. Get someone else to change their nappies during this time if you can. If this isn't possible, wash your hands well after changing their nappy.

More information about this treatment

For further information about this treatment and possible side effects go to the electronic Medicines Compendium (eMC) website. You can find the patient information leaflet on this website.

You can report any side effect you have to the Medicines Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.

  • Electronic Medicines Compendium 
    Accessed October 2022

  • Rituximab for the first-line treatment of chronic lymphocytic leukaemia
    National Institute for Health and Care Excellence (NICE), July 2009

  • Rituximab for the first-line maintenance treatment of follicular non-Hodgkin's lymphoma
    The National Institute for Health and Care Excellence (NICE), 2011​​

  • Non-Hodgkin's lymphoma: rituximab subcutaneous injection
    The National Institute for Health and Care Excellence (NICE), 2014

  • Rituximab for the treatment of relapsed or refractory chronic lymphocytic leukaemia
    National Institute for Health and Care Excellence (NICE), July 2010

  • Polatuzumab vedotin with rituximab and bendamustine for treating relapsed or refractory diffuse large B-cell lymphoma
    National Institute for Health and Care Excellence (NICE), September 2020

Last reviewed: 
21 Oct 2022
Next review due: 
21 Oct 2025

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