This information is designed to tell you about methotrexate, give you some important guidelines about the drug, and to answer some of your questions. After reading the leaflet, please feel free to ask the doctor any questions.
Why have I been prescribed methotrexate?
Methotrexate is used to treat psoriasis and other skin disorders. Methotrexate can reduce inflammation and also can affect the immune system (the body’s own defence system). As one of its actions is to reduce the activity of the immune system, it is always used with care.
When do I take methotrexate?
Methotrexate is usually taken in tablet form once a week on the same day. It should be taken with food. The tablets should be swallowed whole and not crushed or chewed. Methotrexate may also be given once a week by injection.
What dose do I take?
Methotrexate tablets prescribed from hospital are always 2.5 mg strength. Methotrexate is also available as a 10 mg tablet. Unfortunately this looks very similar to the 2.5 mg tablet and serious unintentional overdoses have occurred. If you get methotrexate on prescription from your GP, make certain of the strength of the tablets. Your doctor will advise you about what dose you should take. Usually you will start on a low dose. Your doctor may then increase this. Some patients are given methotrexate by injection.
How long will methotrexate take to work?
Methotrexate does not work immediately. It may be 3–8 weeks before you notice any benefit.
What are the possible side-effects?
• 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 can make you more likely to develop infections. If you develop a severe sore throat or other infection, or if you have a fever, if you develop unexplained bruising or bleeding, or if you develop any new symptoms after starting methotrexate, you should see your doctor.
• Rarely methotrexate causes inflammation of the lung with breathlessness. If you become breathless, you should see your doctor immediately.
• If you have not had chickenpox but come into contact with someone who has chickenpox or shingles, or if you develop chickenpox or shingles while you are taking methotrexate, you should see your doctor immediately as you may need special treatment.
Do I need any special checks while on methotrexate?
Your doctor will arrange for you to have regular blood checks while on methotrexate because the drug can affect the blood count and sometimes cause liver problems.
Can I take other medicines along with 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. You may only take anti-inflammatory drugs if they are prescribed to you by your doctor.
• Do not take 'over-the-counter' preparations without discussing this first with your doctor or pharmacist.
• You should avoid drugs containing trimethoprim (for example Septrin) which is a drug prescribed for infections.
Can I have vaccinations while on methotrexate?
• It is recommended that you should not be immunised 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' polio vaccine 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 vaccination.
• Yearly flu vaccines and pneumovax are safe.
Does methotrexate affect fertility or pregnancy?
Methotrexate can reduce fertility and is likely to harm an unborn baby. Therefore it must not be taken during pregnancy. Whilst taking methotrexate, and for six months after methotrexate is stopped, both women and men using this drug should take contraceptive precautions. If you are planning a family, or if you become pregnant while taking methotrexate, you should discuss this with your doctor as soon as possible. You also should not breastfeed if you are taking methotrexate.
May I drink alcohol while taking methotrexate?
If you drink alcohol you should only drink it in small amounts because methotrexate and alcohol can interact and damage your liver. Discuss this with your doctor.
Where can I obtain further information?
If you would like any further information about methotrexate, or if you have any concerns about your treatment, you should discuss this with your Dermatologist when you attend for your appointment.