Modified de Gramont

Modified de Gramont describes a way of giving the chemotherapy drug fluorouracil in combination with folinic acid (calcium folinate or leucovocrin).

You pronounce Modified de Gramont as mod-i-f-ih-d dee gr-ah-mon. You pronounce fluorouracil as floor-oh-yoor-uh-sil. It is also called 5FU.

Modified de Gramont is a treatment for bowel (colorectal) cancer. 

How does Modified de Gramont work?

Fluorouracil is a chemotherapy drug that works by destroying quickly dividing cells, such as cancer cells. Folinic acid makes the fluorouracil work better.

How do you have Modified de Gramont?

You have fluorouracil and folinic acid 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 Modified de Gramont?

You have Modified de Gramont as cycles of treatment. This means that you have the drugs and then a rest to allow your body to recover. Each cycle of treatment lasts 14 days. You might have 6-12 cycles of treatment.

You have a 1-2 hour drip of folinic acid on the first day. This is followed by an injection of fluorouracil which takes a few minutes. You then go home with a portable pump. The pump gives the correct dose of fluorouracil over 46 hours.

On the third day you go back to the hospital to have the pump disconnected. Or a nurse can come to your home to do this. You then have 11 days with no treatment before starting another cycle.

If you don't have a central line you stay in hospital and have the fluorouracil through a cannula. 


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 starting treatment with fluorouracil (5FU) you have a blood test to check levels of an enzyme called dihydropyrimidine dehydrogenase (DPD). A low DPD level might mean you are more likely to have severe side effects from this chemotherapy, so you may start treatment with a lower amount (dose) of the drug or have a different treatment. Your doctor, nurse or pharmacist will talk to you about this.

What are the side effects of Modified de Gramont?

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. 

Breathless and looking pale

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

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).

Difficulty breathing

Your airway might narrow due to a spasm causing: 

  • shortness of breath
  • coughing
  • wheezing
  • a tight feeling in the chest

This often happens in the morning, at night or after exercise. Contact your advice line or tell your healthcare team if this happens. 

Changes to the level of uric acid in the blood

You might have a high level of uric acid in your blood. This can cause gout. You have regular blood tests during treatment to check this.

An abnormal heart trace (ECG)

This could be caused by not enough blood getting to your heart. Go straight to A&E or call 999 if you have chest pain.  

Rarely you might have heart problems such as an irregular heartbeat or heart attack.  

Sore mouth and throat

It may be painful to swallow drinks or food. Painkillers and mouth washes can help to reduce the soreness and keep your mouth healthy. 

Loss of appetite

You might lose your appetite for various reasons while having cancer treatment. Sickness, taste changes or tiredness can put you off food and drinks.


Contact your advice line if you have diarrhoea. For example, 2 or more extra loose bowel movements than usual each day. If you have a stoma, you might have more output than normal. Your doctor may give you anti diarrhoea medicine to take home with you after treatment.

Try to eat small meals and snacks regularly. It’s best to try to have a healthy balanced diet if you can. You don’t necessarily need to stop eating foods that contain fibre. But if your diet is normally very high in fibre, it might help to cut back on high fibre foods such as beans, nuts, seeds, dried fruit, bran and raw vegetables. 

Drink plenty to try and replace the fluid lost. Aim for 8 to 10 glasses per day.

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. 

Sore, red, peeling palms of hands or soles of feet 

The skin on your hands and feet may become sore, red, or may peel. You may also have tingling, numbness, pain and dryness. This is called hand-foot syndrome or palmar plantar syndrome.

Moisturise your skin regularly. Your healthcare team will tell you what moisturiser to use.

Slow wound healing

It might take longer for wounds to heal while having this treatment. 

Feeling tired, weak and lacking energy (fatigue)

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.

High temperature (fever)

If you get a high temperature, let your healthcare team know straight away. Ask them if you can take paracetamol to help lower your temperature. Go straight to A&E or call 999 if you have chest pain.  

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:

  • red, itchy, watery, sore eyes (conjunctivitis). Rarely you might have eye problems such blurred or double vision, lower eyelid turning outwards, dry eyes, inflammation of the optic nerve, narrowing or blockage of the tear ducts, pain with eye movement, loss of vision or sensitivity to light
  • increased heart rate
  • chest pain that can be severe. Go straight to A&E or call 999 if you have chest pain.  

Rare side effects

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

  • a severe whole body infection (sepsis) - if you feel confused, have slurred speech, breathlessness and shivering or muscle pain contact your advice line or healthcare team straight away
  • a feeling or state of intense excitement and happiness (euphoria)
  • rapid eye movements
  • headache
  • sleepiness or difficulty sleeping
  • dizziness
  • tremors, shaking, stiffness and slow movement (symptoms of Parkinson's disease)
  • low blood pressure
  • not enough fluid in the body (dehydration)
  • ulcers in the food pipe (oesophagus), stomach and bowel
  • uncontrolled bleeding in the digestive system
  • liver damage
  • skin problems including rash, dry skin, increased sensitivity to sunlight, hives, darkening of the skin
  • nail problems including thickening, pain, changes in colour of the nail and nail bed
  • increase in seizures if you already have epilepsy

Other side effects

If you have side effects that aren't listed on this page, you can look at the individual fluorouracil (5FU) drug page.

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 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 

You may not be able to become pregnant or father a child after treatment with these drugs. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.

Men might be able to store sperm before starting treatment. And women might be able to store eggs or ovarian tissue. But these services are not available in every hospital, so you would need to ask your doctor about this.    

Contraception and pregnancy

This treatment may harm a baby developing in the womb. It is important not to become pregnant or father a child while you are having treatment.

Women must not become pregnant for at least 6 months after the end of treatment. Men should not father a child for at least 3 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. This is because the drugs may come through in 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.

Related links