Updated February 2023

What is methotrexate?

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Methotrexate is a medication used to treat certain childhood rheumatic conditions (diseases which may affect joints, muscles, skin or eyes). These include juvenile arthritis (JIA), lupus (also known as SLE), uveitis, dermatomyositis and scleroderma.

Methotrexate is a medication that works by suppressing the immune system. It reduces the damage done by inflammation, rather than just reducing pain. Because of this, it is called a disease modifying antirheumatic drug (DMARD). Other medications in this group include leflunomide, sulfasalazine and hydroxychloroquine.

Methotrexate is thought to work by affecting the immune system. It has been safely used for over 30 years. It is one of the most common medications used by rheumatologists. It is also used at very high doses to treat some childhood cancers.

Important things to remember

  • You must see your rheumatologist regularly to make sure the treatment is working and check for possible side effects.
  • You should have regular blood tests as suggested by your rheumatologist.
  • If you are worried about any side effects, you should contact your rheumatologist as soon as possible.
  • If you stop methotrexate for any reason, you must contact your rheumatologist.

How will it help?

Methotrexate works slowly. You can expect your child to start feeling better, but it might take one to three months.

How is methotrexate given?

Methotrexate can be given as an oral tablet or an injection under the skin.

When should it be given?

It is taken once a week, on the same day every week. It must not be given every day.

What is the dose?

This depends on the size and weight of your child. It also depends on how extensive the disease is.

How long will it be used for?

Methotrexate can be continued long-term to maintain disease control.

Are there any side effects?

Methotrexate is usually very effective in improving your child’s condition, but as with all medications side effects can occur. Some are common, and some are rare. Most people don’t have any problems when they take methotrexate. Folic acid (a vitamin) is usually given to children on methotrexate to make these side effects less likely.


Most common side effects


Nausea (feeling sick) vomiting, loss of appetite & diarrhoea

  • Folic acid
  • Anti-emetics (anti-sickness medication)
  • May be reduced by giving methotrexate by injection

Skin rash/ sun sensitivity

  • Use high factor sunscreen and hats

Mouth ulcers

Sore gums

Sore throat

  • Folic acid

Rare side effects


May cause hair thinning

Disturbance in blood counts (change in blood test results)

Upset liver function

  • Usually returns to normal if methotrexate dose is reduced or stopped

Things you need to know when your child is taking this medication

What to do if your child is sick
It is safe to give methotrexate if your child has a mild cold or cough. Don’t give methotrexate if your child:

  • Has a high fever
  • Has had vomiting/diarrhoea  
  • Has been in contact with chickenpox
  • Is sick and you’re not sure why.

If you’re not sure, talk to your doctor and get them checked if necessary before giving methotrexate.

Methotrexate can interact with other medications, including over-the-counter and herbal /naturopathic medications. Always discuss any new medication with your doctor before taking it. Methotrexate can safely be given with non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen, with appropriate monitoring.

Most immunisations are safe to have (flu vaccine, cervical cancer vaccine, killed polio vaccine (IPV) etc) when taking this medication. Live virus vaccines (such as mumps, measles, rubella (MMR), polio (OPV)), varicella (chicken pox) and some live vaccines should not be used.

As methotrexate affects the immune system and can affect the body’s ability to fight infections, contact with adults and children who have contagious illnesses like chickenpox should be avoided where possible. You should report any sign of infection, e.g. fever, to your child’s doctor. Methotrexate can make chickenpox infections more serious. A blood test can be done to see if your child is already immune to chickenpox. If your child is in contact with chickenpox or shingles, call your doctor.

Methotrexate and alcohol are both broken down by the liver. Drinking alcohol while you are on this medication can put extra strain on the liver. It is not known how much is safe, so it is suggested that anyone on methotrexate should avoid drinking alcohol.

Sexual health and pregnancy 
Being pregnant while on methotrexate, can be harmful for the baby. Patients who are sexually active, should use effective contraception to avoid getting pregnant. This should be continued for six months after methotrexate is finished. Having been on methotrexate in the past does not change a person’s fertility for the future nor does it change their chances of having babies later.

Myths and misconceptions
You may hear a lot of different information about methotrexate from friends, pharmacists or people that you know. If you are worried about anything, please talk to your child’s doctor or nurse for more information. If your child is taking methotrexate they should see their paediatric rheumatologist regularly to make sure the treatment is working and to minimise any possible side effects.