What is CMF?

CMF is used to treat breast cancer. It is best to read this information with our general information about chemotherapy and the type of cancer you have.

CMF comes from the initials of the drugs used:

Your doctor will talk to you about this treatment and its possible side effects before you agree (consent) to have treatment.

DPD testing before treatment

Before starting this treatment, you should have a blood test to check whether you have low levels of an enzyme called DPD. This is called DPD deficiency. People who have low DPD levels can develop serious or life-threatening side effects if they have 5FU. If you have DPD deficiency, this can affect the treatments that are available for you.

You will not know without a test if you have DPD deficiency, as there are no symptoms. Testing can detect most cases of DPD deficiency, but not all cases. You can talk to your cancer doctor about your risk of having DPD deficiency before you start treatment.

How CMF is given

You will be given CMF in the chemotherapy day unit or during a stay in hospital. A chemotherapy nurse will give it to you.

During treatment you usually see a cancer doctor, a chemotherapy nurse or a specialist nurse, and a specialist pharmacist. This is who we mean when we mention doctor, nurse or pharmacist in this information.

Before or on the day of treatment, a nurse or person trained to take blood (phlebotomist) will take a blood sample from you. This is to check that your blood cells are at a safe level to have chemotherapy. 

You will see a doctor or nurse before you have chemotherapy. They will talk to you about your blood results and ask you how you have been feeling. If your blood results are okay, the pharmacist will prepare your chemotherapy. Your nurse will tell you when your treatment is likely to be ready. 

Your nurse usually gives you anti-sickness (anti-emetic) drugs before the chemotherapy. You may have the chemotherapy drugs through: 

  • cannula – a short, thin tube the nurse puts into a vein in your arm or hand
  • a central line – a fine tube that goes under the skin of your chest and into a vein close by
  • a PICC line – a fine tube that is put into a vein in your arm and goes up into a vein in your chest
  • an implantable port (portacath) – a disc that is put under the skin on your chest or arm and goes into a vein in your chest
  • as tablets that you swallow.

Your course of chemotherapy

You usually have a course of several cycles of treatment over a few months. Your nurse or doctor will talk to you about how the treatment will be given. They may give you a copy of a treatment plan to take home with you.

Usually, your nurse gives you cyclophosphamide, methotrexate and 5 FU on the first day. This is day 1 of treatment. You will then have the same treatment a week later (day 8). You then have a rest period before starting another cycle. Each cycle usually takes 28 days (4 weeks).

Sometimes the cyclophosphamide is given as tablets instead of an injection. You take the tablets every day, starting on day 1, for 2 weeks.

Your doctors will tell you how many cycles of treatment you will have.

CMF is sometimes given as a 21day cycle. Your doctors will explain your treatment plan to you.

Taking cyclophosphamide tablets

The nurse or pharmacist will give you the tablets to take home. Always take them exactly as explained. This is important to make sure they work as well as possible for you. 

Your nurse or pharmacist may also give you anti-sickness drugs and other medicines to take home. Take all your capsules or tablets exactly as they have been explained to you.

The tablets must be swallowed whole with a glass of water. They should not be chewed or crushed.

Take them early in the day and drink plenty of fluid.  Take them at the same time every day. Try to take the tablets on an empty stomach. But if this causes you to feel sick (nausea), then take them with or after food.

If you forget to take the tablets, you should take the missed dose as soon as possible within the same day. If a full day has gone by, let your doctor or nurse know. Do not take a double dose unless your doctor tells you to.

Other things to remember about your tablets:

  • Wash your hands after taking your tablets.
  • Other people should avoid direct contact with the chemotherapy drugs. 
  • Keep them in the original package and at room temperature, away from heat and direct sunlight..
  • Keep them safe and out of sight and reach of children.
  • If you are sick just after taking the tablets, contact the hospital. Do not take another dose.
  • If your treatment is stopped return any unused tablets to the pharmacist.

Folinic acid tablets

Your doctor may give you folinic acid tablets to take 24 hours after having the methotrexate. They may do this if you have severe side effects from methotrexate, such as:

  • a very sore mouth or eyes
  • severe diarrhoea.

About side effects

We explain the most common side effects of this treatment here. We also include some less common side effects.

You may get some of the side effects we mention, but you are unlikely to get all of them. You may have some rarer side effects that we have not listed here. Always tell your doctor, nurse or pharmacist about any side effects you have.

Your doctor, nurse or pharmacist can give you drugs to help control some side effects. It is important to take them exactly as they tell you. This means the drugs will be more likely to work for you. Your doctor, nurse or pharmacist will give you advice about managing your side effects. After your treatment is over, most side effects start to improve.

Serious and life-threatening side effects

Some cancer treatments can cause severe side effects. Rarely, these may be life-threatening. Your cancer doctor, nurse or pharmacist can explain the risk of these side effects to you.

If you have low levels of an enzyme called DPD (DPD deficiency), you may have a higher risk of severe or life-threatening side effects.

Contact the hospital

Your nurse will give you telephone numbers for the hospital. If you feel unwell or need advice, you can call them at any time of the day or night. Save these numbers in your phone or keep them somewhere safe.

More information

We cannot list every side effect for this treatment. There are some rare side effects that are not listed. You can visit the electronic Medicines Compendium (eMC) for more detailed information.

Side effects while treatment is being given

Some people may have side effects while they are being given the chemotherapy or shortly after they have it:

Allergic reaction

Some people have an allergic reaction while having this treatment. Before treatment, you will be given medicines to help prevent or reduce any reaction.

Signs of a reaction can include:

  • feeling hot or flushed
  • shivering
  • itching
  • a skin rash
  • feeling dizzy
  • a headache
  • feeling breathless or wheezy
  • swelling of your face or mouth
  • pain in your back, tummy or chest.

Your nurse will check you for signs of a reaction during your treatment. If you feel unwell or have any of these signs, tell them straight away. If you do have a reaction, it can be treated quickly.

Sometimes a reaction happens a few hours after treatment. If you develop any signs or feel unwell after you get home, contact the hospital straight away.

The drug leaks outside the vein

If the drug leaks outside the vein, it can damage the surrounding tissue. This is called extravasation. Extravasation is not common but if it happens it is important to treat it quickly. Tell your nurse straight away if you have any stinging, pain, redness or swelling around the vein.

If you get any of these symptoms after you get home, contact the doctor or nurse straight away on the contact telephone number they gave you.

Pain along the vein

You may get pain at the place where the injection is given or along the vein. If you feel pain, tell your nurse or doctor straight away so that they can check the site. They may give the drug more slowly or flush it through with more fluid to reduce pain.

Common side effects

Risk of infection

This treatment can reduce the number of white blood cells in your blood. These cells fight infection. If the number of white blood cells is low, you are more likely to get an infection. A low white blood cell count is sometimes called neutropenia.

An infection can be very serious when the number of white blood cells is low. It is important to get any infection treated as soon as possible. Contact the hospital straight away on the 24-hour contact number you have been given if:

  • your temperature goes over 37.5°C (99.5°F)
  • you suddenly feel unwell, even with a normal temperature
  • you have symptoms of an infection
  • your temperature goes below 36°C (96.8°F).

Symptoms of an infection include:

  • feeling shivery and shaking
  • a sore throat
  • a cough
  • breathlessness
  • diarrhoea
  • needing to pass urine (pee) a lot, or discomfort when you pass urine.

It is important to follow any specific advice your cancer treatment team gives you.

The number of white blood cells will usually return to normal before your next treatment. You will have a blood test before having more treatment. If your white blood cell count is low, your doctor may delay your treatment for a short time, until your cell count increases.

Bruising and bleeding

This treatment can reduce the number of platelets in your blood. Platelets are cells that help the blood to clot.

If the number of platelets is low, you may bruise or bleed easily. You may have:

  • nosebleeds
  • bleeding gums
  • heavy periods
  • blood in your urine (pee) or stools (poo)
  • tiny red or purple spots on the skin that may look like a rash.

Tell your doctor if you have any unexplained bruising or bleeding. You may need a drip to give you extra platelets. This is called a platelet transfusion.

Anaemia (low number of red blood cells)

This treatment can reduce the number of red blood cells in your blood. Red blood cells carry oxygen around the body. If the number of red blood cells is low, this is called anaemia. You may have symptoms such as:

  • pale skin
  • lack of energy
  • feeling breathless
  • feeling dizzy and light-headed.

Tell your doctor or nurse if you have these symptoms.

If you are very anaemic, you may need a drip to give you extra red blood cells. This is called a blood transfusion.

Bladder problems

Cyclophosphamide may irritate your bladder and cause discomfort when you pass urine (pee). Make sure you drink plenty of fluids during the 24 hours following chemotherapy. Try to drink at least 2 litres (3 ½ pints). It is also important to empty your bladder regularly and to try to pass urine as soon as you feel the need to go.

Contact the hospital straight away if you:

  • feel any discomfort or stinging when you pass urine 
  • notice any blood in it.

Feeling sick

Your doctor will give you anti-sickness drugs to help prevent or control sickness during your treatment. Take the drugs exactly as your nurse or pharmacist tells you. It is easier to prevent sickness than to treat it after it has started.

If you feel sick, take small sips of fluids often and eat small amounts regularly. It is important to drink enough fluids. If you continue to feel sick, or are sick (vomit) more than once in 24 hours, contact the hospital as soon as possible. They will give you advice. Your doctor or nurse may change the anti-sickness drug to one that works better for you.

Loss of appetite

This treatment can affect your appetite. Don't worry if you do not eat much for a day or 2. But if your appetite does not come back after a few days, or if you are losing weight, tell your nurse or dietitian. They can give you advice. They may give you food or drink supplements. Or they may suggest changes to your diet or eating habits to help.

Sore mouth and throat

This treatment may cause a sore mouth and throat. You may also get mouth ulcers. This can make you more likely to get a mouth or throat infection. Use a soft toothbrush to clean your teeth or dentures in the morning, at night and after meals.

If your mouth or throat is sore:

  • tell your nurse or doctor – they can give you a mouthwash or medicines to help
  • try to drink plenty of fluids
  • avoid alcohol, tobacco, and foods that irritate your mouth and throat.

Sucking ice chips may sometimes help relieve mouth or throat pain. But if you are having radiotherapy to the head or neck, do not suck on ice. It can cause damage.

Diarrhoea

This treatment may cause severe diarrhoea. Diarrhoea means passing more stools (poo) than is usual for you, or having watery or loose stools. If you have a stoma, it will be more active than usual.

Your hospital team may give you anti-diarrhoea drugs to take at home.

If you have diarrhoea or a mild increase in stoma activity:

  • follow any advice from your cancer team about taking anti-diarrhoea drugs
  • drink at least 2 litres (3½ pints) of fluids each day
  • avoid alcohol, caffeine, milk products, high-fat foods and high-fibre foods.

Contact the hospital straight away if:

  • you have diarrhoea at night
  • you have diarrhoea more than 4 times in a day
  • you have a moderate or severe increase in stoma activity
  • the anti-diarrhoea drugs do not work within 24 hours.

You may need to go to hospital to have fluids through a drip.

Constipation

This treatment can cause constipation. Constipation means that you are not able to pass stools (poo) as often as you normally do. It can become difficult or painful. Here are some tips that may help:

  • Drink at least 2 litres (3½ pints) of fluids each day.
  • Eat high-fibre foods, such as fruit, vegetables and wholemeal bread.
  • Do regular gentle exercise, like going for short walks.

If you have constipation, contact the hospital on the 24-hour number for advice. They can give you drugs called laxatives to help. 

If you have not been able to pass stools for over 2 days and are being sick, contact the 24-hour number straight away. 

Indigestion

This treatment may cause heartburn or reflux. Tell your doctor or nurse if you experience this. Your doctor can give you medicines to help.

Hair loss

Your hair will get thinner. Or you may lose all the hair from your head. You may also lose your eyelashes and eyebrows, as well as other body hair. Hair loss usually starts after your first or second treatment.

Your nurse can talk to you about ways to cope with hair loss. There are ways to cover up hair loss if you want to. Your scalp may be sensitive. It is important to cover your head to protect your skin when you are out in the sun.

Hair loss is almost always temporary. Your hair will usually grow back after treatment finishes.

Feeling tired

Feeling tired is a common side effect of this treatment. It is often worse towards the end of treatment and for some weeks after it has finished. Try to pace yourself and plan your day so you have time to rest. Gentle exercise, like short walks, can give you more energy.

If you feel sleepy, do not drive or use machinery.

Eye problems

This treatment may make your eyes feel sore, red and itchy (conjunctivitis). Your doctor can prescribe eye drops to help treat this. Your pharmacist will tell you how to use your eye drops. It is important to follow their advice.

It may also make your eyes more sensitive to light and cause blurry vision. If you have pain or notice any change in your vision, always tell your doctor or nurse.

Headaches

This treatment may cause headaches. If you have headaches, tell your doctor. They may give you painkillers to help.

Less common side effects

Skin changes

CMF may affect your skin. Your doctor or nurse can tell you what to expect. If your skin feels dry, try using an unperfumed moisturising cream every day. CMF can cause a rash, which may be itchy.

During treatment and for several months afterwards, you will be more sensitive to the sun and your skin may burn more easily than usual. If you are out in the sun, use a suncream with a high sun protection factor (at least SPF 30) to protect your skin.  You should also cover up with clothing and a hat.

If you have ever had radiotherapy, the area that was treated may become red or sore. Your skin may darken. People with darker skin may develop noticeable light patches on their skin.

Always tell your doctor or nurse about any skin changes. They can give you advice and may give you creams or medicines to help. Any changes to your skin are usually temporary and improve when treatment finishes.

Very rarely, a much more serious skin condition can occur. You may have a skin rash which then blisters and your skin can peel. You may also feel unwell with flu-like symptoms such as a high temperature and joint pain. If you have any of these symptoms, contact your doctors straight away.

Nail changes

This treatment can affect your nails. They may grow more slowly or break more easily. You might notice ridges or white or dark lines across your nails. Sometimes nails can become loose or fall out. When treatment finishes, any changes usually disappear as the nails grow out.

There are things you can do to look after your nails:

  • Moisturise your nails and cuticles regularly.
  • Keep your nails clipped short.
  • Wear gloves to protect your nails when you are doing things in the house or garden.
  • Keep your hands and nails clean to help avoid infection, but avoid bathing in very hot water.
  • Do not use false nails, gels or other acrylics during this treatment, as they may increase the risk of infection.
  • It is fine to wear nail varnish, but try to use a water-based polish. Avoid using harsh chemicals, such as acetone, when taking off the polish.
  • If your toenails are affected, wear well-fitted shoes to cushion them.

Tell your doctor or nurse if you notice changes to your nails. They can give you advice or arrange for you to see a podiatrist for foot care advice if needed.

Changes to your taste

You may get a bitter or metal taste in your mouth. Sucking sugar-free sweets may help with this. Some foods may taste different or have no taste. Try different foods to find out what tastes best to you. Taste changes usually get better after treatment finishes. Your nurse can give you more advice.

Changes in the way the heart works

5FU can affect how the heart works. You may have tests to see how well your heart is working. These may be done before, during and after treatment.

It is still possible for the heart to be affected even if these test results are normal. Very rarely, this can cause heart failure or a heart attack. The risk of this happening is very low (less than 1 in 100 or 1%). But it is important that you know about it.

Call your doctor straight away on the 24-hour number the hospital has given you if you have any of these symptoms at any time during treatment:

  • pain or tightness in your chest
  • breathlessness
  • changes to your heartbeat.

If you cannot get through to your doctor, call the NHS urgent advice number which is 111.

Effects on the lungs

This treatment can cause changes to the lungs. Tell your doctor if you develop:

  • a cough
  • wheezing
  • breathlessness.

You should also tell them if any existing breathing problems get worse. You may have tests to check your lungs.

Effects on the kidneys and liver

This treatment can affect how your kidneys and liver work. This is usually mild and goes back to normal after treatment. You will have blood tests to check how well your kidneys and liver are working.

It is important to drink at least 2 litres (3½ pints) of fluids each day to help protect your kidneys.

Second cancer

Cyclophosphamide can increase the risk of developing a second cancer, years later. If a second cancer develops it is usually leukaemia.

But the benefits of treatment outweigh this risk. Your doctor can talk to you about this.

Other information

Blood clot risk

Cancer and some cancer treatments can increase the risk of a blood clot. Contact the hospital straight away on the 24-hour number if you have any of these symptoms during or after treatment:

  • throbbing pain or swelling in a leg or arm
  • reddening of the skin in the area – if you have black or brown skin, this can be harder to notice, but the skin might become darker
  • suddenly feeling breathless or coughing.

Always call 999 if you have:

  • chest pain
  • difficulty breathing.

A blood clot is serious, but it can be treated with drugs called anticoagulants. These thin the blood. Your doctor, nurse or pharmacist can give you more information about preventing and treating blood clots.

Other medicines and food

Some medicines can affect how this treatment works or be harmful when you are having it. Always tell your cancer doctor about any drugs you are taking or planning to take, such as:

  • medicines you have been prescribed
  • medicines you buy in a shop or chemist
  • vitamins, herbal drugs and complementary therapies.

Tell other doctors, pharmacists or dentists who prescribe or give you medicines that you are having this cancer treatment. 

You can visit the electronic Medicines Compendium (eMC) for more detailed information about your treatment. 

During treatment with cyclophosphamide you should avoid grapefruit and grapefruit juice as it may make side effects worse.

Vaccinations

Vaccinations can reduce your risk of getting certain infections. Your doctor or nurse may talk to you about having vaccinations.

Doctors usually recommend that people with cancer have a flu vaccination and a coronavirus (covid) vaccination. These are both inactivated vaccinations that can help reduce the risk of infection. People with weak immune systems can have these, as they are not live vaccinations. 

If your immune system is weak, you need to avoid live vaccinations. This is because they can make you unwell. Live vaccines contain a very weak version of the illness they are vaccinating you against. Your cancer doctor or GP can tell you more about live and inactivated vaccinations.

Contraception

Your doctor will advise you not to get pregnant or make someone pregnant while having this treatment. The drugs may harm a developing baby. It is important to use contraception during your treatment and for a while after treatment finishes. Your doctor, nurse or pharmacist can tell you more about this.

Breastfeeding

You are advised not to breastfeed while having this treatment, or for some time after treatment finishes. This is because the drugs could be passed to the baby through breast milk.

Your doctor or nurse can give you more information.

Fertility

Some cancer drugs can affect whether you can get pregnant or make someone pregnant. If you are worried about this, it is important to talk with your doctor before you start treatment.

Sex

If you have sex during a course of this treatment, you should use barrier protection such as a condom or dental dam. This will protect your partner if any of the drug is in your semen or vaginal fluid.

Changes to periods

If you have a period, these may become irregular or stop while you are having this treatment. This may be temporary, but it can sometimes be permanent. Your menopause may start sooner than it would have done. Your doctor or nurse can give you more information.

Medical and dental treatment

If you need medical treatment for any reason other than cancer, always tell the doctors and nurses you are having cancer treatment. Give them the contact details for your cancer doctor so they can ask for advice.

If you think you need dental treatment, talk to your cancer doctor or nurse. Always tell your dentist you are having cancer treatment.

About our information

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert health professionals and people living with cancer.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

Date reviewed

Reviewed: 01 September 2022
|
Next review: 01 September 2024
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

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