Folinic acid, fluorouracil and irinotecan (FOLFIRI)

FOLFIRI is the name of a combination of cancer drugs. It includes the drugs we list below. Next to each we have how you pronounce it:

  • folinic acid - also called leucovorin, calcium folinate or FA (foh-lin-ik ass-id)

  • fluorouracil - also called 5FU (floor-oh-yoor-uh-sil)

  • irinotecan (i-rin-o-te-can)

It is a treatment for a number of different cancer types. 

FOLFIRI is also known as irinotecan de Gramont or irinotecan modified de Gramont.

How does FOLFIRI work?

Fluorouracil and irinotecan are chemotherapy drugs. They destroy quickly dividing cells, such as cancer cells.

Folinic acid is not a chemotherapy. But you often have it with fluorouracil to help it work better.   

How do you have FOLFIRI?

You have folinic acid, 5FU, and irinotecan 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 FOLFIRI?

You have FOLFIRI as cycles of treatment. This means that you have the drug and then a rest to allow your body to recover.

Each cycle of treatment lasts 2 weeks (14 days). Depending on your needs, you may have up to 12 cycles, taking up to 6 months in total.

Exactly how you have your drugs may depend on your treatment centre and your circumstances. The following is an example:

Day 1
  • You have irinotecan through a drip into the bloodstream over 30 to 120 minutes. This depends on which cycle you are having.
  • You have folinic acid through a drip into the bloodstream over 2 hours.
  • You have an injection of fluorouracil into the bloodstream over 5 minutes.
  • You start fluorouracil as an infusion over 46 hours given by a small portable pump.
Day 2
  • You continue to have the 5FU infusion.
Day 3
  • The pump is disconnected.
Day 4 to 14
  • You have no treatment.

Then you start the cycle again.

5FU pump

You have the fluorouracil (5FU) through a small pump. The pump slowly puts the fluid into your bloodstream (infusion). You can keep the pump in a small bag or attach it to a belt. You’ll need to go back to the hospital after the second day of your treatment to have the pump removed. Or sometimes a chemotherapy nurse may be able to do it for you at home.


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 FOLFIRI?

Side effects can vary from person to person. They also depend on what other treatment you are having. 

When to contact your team

Your doctor, pharmacist or nurse will go through the possible side effects. They will monitor you closely 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

  • the side effects are affecting your daily life

Early treatment can help manage side effects better. 

Contact your advice line, doctor or nurse immediately if you have signs of infection, such as a temperature above 37.5C or below 36C, or if you develop a severe skin reaction. Signs of a severe skin reaction include peeling or blistering of the skin.

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. 

Bruising, bleeding gums or nose bleeds

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).

Breathlessness and looking pale

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

Sore mouth

Mouth sores and ulcers can be painful. Keep your mouth and teeth clean; drink plenty of fluids; avoid acidic foods such as oranges and lemons; chew gum to keep the mouth moist and tell your doctor or nurse if you have ulcers.

Inflammation of the digestive system

You might have inflammation of the digestive system Open a glossary item. Including the throat, the food pipe (oesophagus), and the tummy (stomach). You may find it painful to swallow drinks or food, have heartburn, or have pains in your tummy.

You can also have inflammation of the back passage (rectum) that can cause diarrhoea. Other symptoms are pain, bleeding and discharge from the back passage.

Speak to your doctor, pharmacist, or nurse if you have any of these symptoms, they will tell you what you can take to relieve the symptoms.

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.


Contact your advice line if you have diarrhoea. For example, in one day you have 2 or more loose bowel movements than usual. 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.

Difficulty breathing

You may have difficulty breathing with wheezing and coughing. Let your healthcare team know straight away if this happens. 

Acute cholinergic syndrome

Irinotecan can cause some people to develop a set of side effects during or within the first 24 hours after having the drug. These side effects include diarrhoea which may be severe. Other symptoms are - sweating, stomach cramps, increased production of saliva, and watery eyes. You may have an injection of atropine before the irinotecan to reduce these side effects.

Contact your healthcare team straight away if you have these symptoms within 24 hours of having irinotecan. You’ll need to have treatment to help control them.

Changes in your heart rhythm

These drugs can cause changes to your heart rhythm. So before you start treatment you might have tests to check your heart, such as an electrocardiogram (ECG) Open a glossary item.

Less commonly you may have chest pain, or this treatment might affect the blood flow around the heart. Rarely it might cause a heart attack. Call 999 if you have chest pain.

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.

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. 

Soreness, redness and peeling on palms and 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

Any wounds you might have can take longer to heal. Keep wounds clean to prevent infection. Contact your GP or specialist nurse if you are worried about a wound.

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.

Liver changes

You might have liver changes that are usually mild and unlikely to cause symptoms. 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.

5FU can cause liver cell damage, but this is rare.

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:

  • constipation

  • high temperature (fever)

  • tummy (abdominal) pain

Rare side effects

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

  • an allergic reaction - symptoms include difficulty breathing, dizziness or general swelling of your hands, face, and throat. Let your nurse know straight away if this happens

  • inflammation of the veins

  • blood clots that are life threatening; signs are pain, swelling and redness where the clot is. Feeling breathless can be a sign of a blood clot on the lung. Contact your advice line straight away if you have any of these symptoms

  • feeling sleepy

  • mood changes such as feeling agitated, depressed or feeling very happy (euphoria)

  • feeling confused and disorientated, and having problems with walking or speaking

  • eye problems including eyes moving quickly from side to side (nystagmus), inflammation, blocked tear ducts, blurred vision, double vision, and your eyes can be sensitive to light

  • headaches

  • shaking and trembling, stiffness and slow movement (symptoms of Parkinson's disease)

  • an increase in the muscle tone of your legs and feet causing them to be stiff

  • low blood pressure

  • skin problems such as rash, dry, red inflamed and itchy skin. Increased sensitivity to sunlight, hives, and darkening or lightening of the skin

  • nail problems such as thickening, inflammation, pain, changes in the colour of the nail and nail bed

  • dizziness

  • inflammation of the gall bladder and damage to the bile ducts

  • raised levels of ammonia in the blood - symptoms include feeling irritable, fits (seizures), and problems with coordination and speech

  • changes to the way your kidneys work - you have regular blood tests to check for this

  • changes in the brain that are usually reversible, causing a sudden onset of symptoms including headaches, dizziness, confusion, fits and changes to your vision

  • lack of blood supply to the brain, gastric organs and your arms, legs, fingers and toes

What else do you 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 get someone pregnant 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.    

Pregnancy and contraception

This drug may harm a baby developing in the womb. It is important not to become pregnant while you are having treatment with this drug and for at least 6 months afterwards.

Men having treatment with this drug are advised not to get someone pregnant during treatment and for 3 months after stopping treatment.

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 you're having treatment.


It is not known whether this drug comes through into the breast milk. Doctors usually advise that you don’t breastfeed during this treatment.

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