Raltitrexed (Tomudex)

Raltitrexed is a chemotherapy drug, it is also known as Tomudex.
It is a treatment for bowel (colorectal) cancer that has:

  • a high risk of coming back
  • spread to other parts of the body (advanced or metastatic bowel cancer)

You might also have raltitrexed if you’re unable to have other bowel cancer treatments such as capecitabine, fluorouracil (5FU), oxaliplatin and Modified de Gramont (MdG). 

You have raltitrexed on its own or with other cancer drugs.

How does raltitrexed work?

Raltitrexed is from a group of drugs known as anti metabolites.

These stop cells making and repairing DNA Open a glossary item. Cancer cells need to make and repair DNA in order to grow and multiply.

How do you have raltitrexed?

You have raltitrexed as a drip into your bloodstream (intravenously).  

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.

How often do you have raltitrexed?

You have raltitrexed every 3 weeks (21 days). Each 3 week period is a cycle of treatment Open a glossary item. You usually have between 3 to 8 cycles. Your doctor will tell you how many cycles you need.


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.

What are the side effects of raltitrexed?

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.

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 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. 

Breathlessness and looking pale

You might be breathless and look pale due to a drop in red blood cells. This is called anaemia.

High temperature (fever)

If you get a high temperature, let your health care team know straight away. Ask them if you can take paracetamol to help lower your temperature.

Tiredness and weakness during and after treatment

Tiredness and weakness (fatigue) can happen during and after treatment. Doing gentle exercises each day can keep your energy up. Don't push yourself, rest when you start to feel tired and ask others for help.

Diarrhoea or constipation

Tell your healthcare team if you have diarrhoea or constipation. They can give you medicine to help. 

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.

Skin problems

Skin problems include a skin rash, or less commonly you may have dry and itchy skin This usually goes back to normal when your treatment finishes. Your nurse will tell you what products you can use on your skin to help.

Your skin might become very red, painful, swollen, and start to peel. This is not as common but you should let your doctor or nurse know straight away if this happens.

Mouth sores and ulcers

Mouth sores and ulcers can be painful. It helps to keep your mouth and teeth clean, drink plenty of fluids and avoid acidic foods such as lemons. Chewing gum can help to keep your mouth moist. Tell your doctor or nurse if you have ulcers.

Pain in different parts of your body 

It’s common to feel pain in different parts of your body such as in your mouth and tummy (abdomen). 

You might also get pain in other areas of the body for example pain and stiffness in your joints, but this is not as common.

Tell a member of the team treating you if you have any pain. They can check the cause and give you medicine to help. 

Liver changes

You might have changes in your liver function that are usually mild. Less commonly high levels of a substance called bilirubin can cause symptoms such as yellowing of the skin and whites of the eyes. They usually go back to normal when treatment finishes.

You have regular blood tests to check for any changes in the way your liver is working.

Loss of appetite and weight loss

You might not feel like eating. You might also lose weight, but this is not as common. It is important to eat as much as you can. Eating several small meals and snacks throughout the day can be easier to manage. You can talk to a dietitian if you are concerned about your appetite or weight loss. 

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:

  • dehydration
  • bruising, bleeding gums and nosebleeds due to a drop in platelets (blood cells that help the blood clot)
  • flu-like symptoms such as high temperature, chills and headaches
  • indigestion
  • swelling of the hands and feet
  • increased sweating
  • changes to your taste
  • headaches
  • sore red, itchy, watery eyes - conjunctivitis
  • hair loss or thinning
  • muscle cramps
  • generally feeling unwell (malaise)

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, food and drink

Cancer drugs can interact with some other medicines and herbal products. Tell your doctor or pharmacist about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies.

In particular tell your doctor, nurse or pharmacist if you are taking:

  • vitamins or vitamin supplements
  • medication to thin your blood and stop it clotting such as warfarin and heparin

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.

Contraception and pregnancy

This drug 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 6 months after treatment.

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


Don’t breastfeed during this treatment because the drug may come through into your 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.

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