Methotrexate for Crohn's disease and ulcerative colitis

What is methotrexate?

Methotrexate belongs to a group of medicines called immunosuppressants. It works on inflammatory bowel disease (IBD) by reducing the activity of the immune system which, in turn, reduces inflammation in the bowel.

Methotrexate was first used in 1947 to treat leukaemia and other forms of cancer but in the 1980s it was used in much lower doses to treat conditions such as rheumatoid arthritis and psoriasis and has gone on to be used in treating Crohn’s disease and ulcerative colitis.

Methotrexate is not licensed for use in treating IBD in the UK, however it has safely been used for more than 20 years to help induce and maintain remission in Crohn’s disease and, less commonly, ulcerative colitis. It is usually prescribed to people who have recurrent flares which need steroids to control them and people who haven’t responded to other medications (such as azathioprine).

It is known under several different brand names including Trexall, rheumatrex and may be referred to as just MTX.

How is methotrexate taken?

Methotrexate is taken once a week either by tablet or injection.


These should be taken after food on the same day each week. The tablets come in two doses - 2.5mg and 10mg. When you pick up a new prescription of your tablets you should always make sure that you have the right dosage to prevent overdosing.


There are two types of injection for methotrexate - subcutaneous (under the skin) and intra-muscular (into the muscle). A nurse at a clinic may administer the injections or you may be trained to do them yourself at home. The injections should be carried out on the same day each week.

It can take up to three months to work and therefore you may be given other medication to take during this time to help control your IBD. If methotrexate is effective for you then you may take it for several years, or as long as you can tolerate it.

You may also be prescribed folic acid to take at the same time as methotrexate can cause you to develop levels of folate that are lower than normal. The folic acid tablets also help your body to cope with the medication and may reduce some of the side effects.


Can methotrexate be taken with other medication?

There are some medications that can interact with methotrexate so you should inform your doctor about any medications or other remedies, vitamins or complementary therapies you are taking. You should be particularly cautious with antibiotics such as co-trimoxazole and trimethoprim and non-steroidal anti-inflammatory medications like ibuprofen.

Some doctors prescribe methotrexate to be taken at the same time as biologic medications and this is safe to do so.

Oral contraceptives can be taken at the same time as methotrexate.

Are there any potential side effects of methotrexate?

As with any medication there may be some undesirable effects while taking it. All the potential side effects will be listed in the patient information leaflet which accompanies your medication. Common side effects of taking methotrexate can include:

  • Feeling sick, vomiting and diarrhoea or feeling drowsy at the beginning of treatment
  • Rarely your lungs can be affected by methotrexate. Speak to your doctor if you are breathless or have a persistent cough, chest pain or find it difficult to breathe
  • Methotrexate can damage the liver. You should have regular blood tests to monitor this and speak to your doctor if you notice any yellowing of your skin
  • Rarely the kidneys are affected by methotrexate. You should have regular liver tests
  • Bone marrow suppression can happen to people taking methotrexate. This means that your white blood cell and platelet count can drop. Signs include bruising easily, nosebleeds, blood spots or rashes on skin
  • Methotrexate can cause aneamia. You should have regular blood tests to show if you have this
  • You may find you are more sensitive to the sun and methotrexate can increase the risk of some forms of skin cancer. You should keep out of the sun or cover up
  • Some people have reported hair loss from taking methotrexate

Is there anything I should know about methotrexate?

  • You should have blood tests before you start the medication. These should include kidney and liver tests. Methotrexate can affect blood count and occasionally cause liver problems. If your liver or kidney function isn’t working properly then you may not be able to take the medication. You may also be given a chest x-ray or other scans
  • If you are female you should be sure that you are not pregnant before starting methotrexate as it may affect the health of your unborn baby
  • Men should be aware that methotrexate has been reported to affect the formation of sperm, therefore both men and women are advised not to conceive if one of the couple is on methotrexate
  • You will need to have regular monitoring to make sure that taking methotrexate continues to be safe for you
  • It is advised that women who are breastfeeding while on methotrexate should speak to their doctor as the medication can pass through the mother’s milk to the baby
  • Because methotrexate impacts on the body’s immune system you many be more prone to catching infections. Even minor infections could become serious so you should try to keep away from people who are unwell. If you haven’t had chicken pox then you may be required to have a vaccine before starting methotrexate to prevent you catching it

You should not receive any live vaccines (measles, mumps, rubella ie MMR, chickenpox, oral polio, BCG, oral typhoid and yellow fever) while taking methotrexate. The flu vaccine injection is safe, but the nasal version for children is not. You should also speak to your doctor if anyone you are in contact with is due to have a live vaccine as it may not be safe for you to be around them afterwards.

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