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Methotrexate
What are the aims of this leaflet?
This leaflet has been written to help you understand more about methotrexate. It tells you what it is, how it works, how it is used to treat skin conditions, and where you can find out more about it.
What is methotrexate and how does it work?
Methotrexate is a drug that acts to slow the proliferation of cells. It was used first, in high doses, to treat cancer, but was found to be an effective treatment for skin and joint diseases at much lower doses than those used for treating cancer. Methotrexate can reduce inflammation and can also affect the immune system (the body's own defence system). One of its actions is to reduce the activity of the immune system, so it is always used with care.
Which skin conditions are treated with methotrexate?
Methotrexate is used to treat psoriasis, psoriatic arthritis, and several other types of skin problem including: pemphigoid, pemphigus, sarcoidosis, scleroderma, dermatomyositis and eczema.
How long will I need to take methotrexate before it has an effect?
Methotrexate does not work immediately. It may be 3-12 weeks before you notice any benefit.
When should I take methotrexate?
Methotrexate is usually taken in tablet form ONCE A WEEK, on the same day each week. The tablets should be swallowed whole and not crushed or chewed. Methotrexate may also be given once a week by injection - either subcutaneous (an injection under the skin, like insulin injections for diabetes), or intramuscular (in the buttocks or thigh).
The 2.5mg tablets are recommended for use as this allows for flexibility in the dose. They should not be confused with 10mg tablets, which can look similar. Care should be taken to ensure that the correct strength has been prescribed and dispensed. You should always check the dose and strength before taking methotrexate.
What dose should I take?
Your doctor will advise you on the dose, and should give you a test dose (usually 2.5 to 5mg) 1 week before starting regular treatment. For severe psoriasis, the usual dose is 10-25 mg orally, once weekly. This should be adjusted according to your response to treatment and side effects. Your doctor may then increase this. Some patients are given methotrexate by injection.
What are the possible side effects of methotrexate?
In some patients methotrexate can cause a feeling of sickness, diarrhoea, mouth ulcers, hair loss and skin rashes. Taking methotrexate can affect the blood count (one of the effects is that fewer blood cells are made) and so can make you more likely to develop infections.
| You should see your doctor if: |
- You develop a sore throat or any other infection.
- You have a fever.
- You develop unexplained bruising or bleeding.
- You develop any new symptoms after starting methotrexate.
| Folic acid is frequently recommended as a vitamin supplement that may reduce the incidence of side effects. Practice varies, and it is best to follow your doctor’s recommendation.
If you have not had chicken-pox, but come into contact with someone who has chicken-pox or shingles, or if you develop chicken-pox or shingles while you are taking methotrexate, you should see your doctor immediately as you may need special treatment.
Are there any other side effects if methotrexate is taken for a long time?
Rarely methotrexate causes inflammation of the lung with breathlessness. If you become breathless, you should see your doctor immediately. Your doctor may also request a chest x-ray before you start treatment.
Long-term methotrexate can increase the risk of cirrhosis of the liver, particularly if there are other factors such as taking alcohol.
How will I be monitored for the side effects of methotrexate treatment?
Because methotrexate can affect the blood count, and sometimes causes liver problems, your doctor will arrange for you to have regular blood checks while you are taking it. You must not take methotrexate unless you are having these regular blood checks. They are done weekly when the dose is being changed, and not less often than every 2-3 months when the dose is stable.
Signs of infection such as a sore throat, mouth ulceration, diarrhoea and sensitivity to sunlight, may signal too much methotrexate. They should be reported immediately and investigated.
The effects of methotrexate on the liver are checked in these blood tests, and sometimes infrequent liver biopsies are required to monitor these effects too.
Can I have vaccinations whilst on methotrexate?
It is recommended that you should not be immunized using any of the 'live' vaccines such as polio, rubella (German measles) and yellow fever. An 'inactivated' polio vaccine can be given instead of the 'live' one and the 'inactivated' version should also be given to people you are in close contact with, such as members of your household.
If you are on methotrexate you should avoid contact with children who have been given the 'live' polio vaccine, for 4-6 weeks after the vaccination. Yearly 'flu vaccines and Pneumovax are safe and recommended.
Does methotrexate affect fertility or pregnancy?
Methotrexate can reduce fertility and it is likely to harm an unborn baby, so it must not be taken during pregnancy. While on methotrexate, and for at least 3 months, and preferably for 6 months, after the methotrexate has been stopped, both women and men should take contraceptive precautions.
If you are planning a family, or if you become pregnant while on methotrexate, you should discuss this with your doctor as soon as possible. You should also not breast feed if you are taking methotrexate.
May I drink alcohol while I am taking methotrexate?
Alcohol does interact with methotrexate. Both alcohol and methotrexate can damage the liver, so it is best to avoid alcohol entirely.
Can I take other medicines at the same time as methotrexate?
Some drugs interact with methotrexate, so you should always let any doctor treating you know that you are taking methotrexate. Special care is needed with non-steroidal anti-inflammatory drugs such as aspirin, ibuprofen and neurofen. You may only take anti-inflammatory drugs if your doctor prescribes them for you. Do not take 'over-the-counter' preparations without discussing this first with your doctor, nurse or pharmacist. You should avoid drugs containing trimethoprim.
Where can I find out more about methotrexate?
If you want to know more about methotrexate, or if you are worried about your treatment, you should speak to your doctor or pharmacist. This information sheet does not list all of the side effects of methotrexate. For fuller details, look at the drug information sheet which comes as an insert with your prescription for methotrexate.
The British Skin Foundation fund vital research into all skin diseases. To find out how you can help, please visit the British Skin Foundation website here.
(While every effort has been made to ensure that the information given in this leaflet is accurate, not every treatment will be suitable or effective for every person. Your own doctor will be able to advise in greater detail)
BRITISH ASSOCIATION OF DERMATOLOGISTS
PATIENT INFORMATION LEAFLET
PRODUCED DECEMBER 2004
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