Medicine Services

Mycophenolate Mofetil (MMF)

This information has been produced to give you details about Mycophenylate Mofetil (MMF) and aims to answer any questions that you may have.

Why would you need to take MMF?Show [+]Hide [-]

MMF is a powerful drug which acts by damping down the immune system and therefore controlling the inflammation in your bowel. It will be prescribed for you either to try and reduce the amount of steroids you might need, or where the steroid tablets have not been effective in controlling your symptoms or where other treatments have failed. It can take up to four months before MMF takes its full effect.

How and when to take MMFShow [+]Hide [-]

MMF is taken in tablet form. It comes in 250mg tablets or in 500mg tablets. The dose of MMF is normally taken in a divided dose of morning and evening. If you accidentally miss a dose please do not take a double dose next time, just take your next normal dose. Missing one dose will not do you any harm.

Can other medicines be taken with MMF?Show [+]Hide [-]

Mycophenolate Mofetil (MMF) can interact with:

  • Antacids (eg aluminium hydroxide and Gaviscon) can reduce the absorption of mycophenolate mofetil.
  • Antiepileptic drugs such as phenytoin are less well absorbed whentaken with mycophenolate mofetil.
  • The tranquilliser Clozapine increases the risk of a fall in white blood cell count and lowers defence against infection.
  • Mycophenolate mofetil interacts with some antiviral drugs including aciclovir and ganciclovir.
  • Lipid-regulating drugs (eg cholestyramine) can affect the absorption of mycophenolate mofetil.

Live vaccines should be avoided when on MMF and other vaccines may be less effective. The live vaccines to avoid are measles, mumps, rubella, polio (oral), BCG, typhoid (oral) and yellow fever.

Does MMF affect fertility or pregnancy?Show [+]Hide [-]

You must not become pregnant whilst on mycophenolate mofetil, and for at least six weeks after stopping the drug. You should not breast feed if you are taking MMF.

Are there any side effects and what are they?Show [+]Hide [-]

  • Sickness, dizziness and fever. This normally settles as your body gets used to the treatment.
  • Blood, liver problems and jaundice. This is why you have regular blood tests while you are taking MMF. These blood tests will pick up any problems before they cause you any symptoms. If a problem does occur then stopping the tablets usually reverses this. Your doctor will advise you.
  • Pancreatitis may occur but is rare. It causes abdominal pain, different to the pain you get from your inflammatory bowel disease. This will settle after stopping the treatment but may require a short stay in hospital.
  • If whilst taking MMF you develop severe flu-like symptoms, severe sore throat, any symptoms of infection or any unexplained bruising, bleeding or jaundice (yellowing of the skin and/or eyes) then you must stop your treatment and inform your consultant or your nurse specialist. A blood test will need to be taken to check that your white cell count has not fallen too low and that your liver and kidneys are still functioning correctly.
  • Cancer risk

There is considerable uncertainty as to whether long-term MMF increases the risk of cancer in Inflammatory Bowel Disease, particularly lymphomas.

Similarly, skin cancer risk may be increased with excess exposure to sunlight although this is uncommon; patients on long-term MMF should avoid excessive exposure to sunlight. To further protect the skin it is recommended that patients should use a good quality sun cream with UVA and UVB protection; an SPF of 30+ with a five star UVA rating is recommended, and you should look for broad spectrum on the label. This needs to be applied at least 20 minutes before going outside and then again every two to three hours. Ensure that you coat all visible skin; the sun cream should remain visible on your skin. Do not rub it all in.

Other rare side effects include:

  • Skin - acne, cold sores, shingles, hair loss itching
  • Urinary - kidney problems urgent need to pass urine
  • GI Tract - swelling of gums or mouth ulcers, loss appetite, diarrhoea can be a problem with high dose of MMF
  • Nerves or senses - convulsions tremor, dizziness, depression, drowsiness, muscle spasms, anxiety
  • Metabolic and vascular - weight loss, gout, high blood sugar, changes in blood pressure, abnormal heart beat
  • Lungs - pneumonia, bronchitis, shortness of breath, cough, fluid on lungs or chest, sinus problems.

Why is careful monitoring important?Show [+]Hide [-]

Monitoring the effects of your new treatment is extremely important and we need to check your blood regularly in order to identify any potential problems. This will be carried out weekly for the first four weeks then fortnightly for four weeks, then monthly until we are satisfied that that your blood results are stable, you will then be able to have your bloods checked every three months. At this time we will also ask you to bring a urine sample to check your kidney function.

This monitoring will be carried out either by your own GP or by your hospital consultant. The most important aspect of this monitoring is to ensure that the white blood cell count does not fall too low while you are on treatment.


  • Please attend regularly for your blood tests
  • Take your tablets as prescribed
  • Do not increase the dose of Mycophenolate mofetil without medical advice
  • Do not give these tablets to anyone else, even if they have similar symptoms

Please let us know if you change your address.

More informationShow [+]Hide [-]


  • Dr N Thompson, tel: 0191 213 7209
  • Sister Elaine Stoker, tel: 0191 223 1208 or 0191 244 8403, 9.00am - 4.00pm Monday - Friday.

This information was produced by Dr N Thompson Consultant Gastroenterologist, and Sister Elaine Stoker Advanced Nurse Practitioner.


You can also download and print a PDF version of this leaflet.

© Copyright Newcastle upon Tyne Hospitals NHS Foundation Trust 2020 Site by TH_NK