Examples

Generic Name
methotrexate

Methotrexate is a medicine taken orally once a week or in 3 divided doses taken at 12-hour intervals during a 24-hour period (for instance, taken at 8 a.m., at 8 p.m., and then again at 8 a.m.).¹

It may also be given as a shot once a week.

How It Works

Methotrexate slows the rapid growth of skin cells in psoriasis.

Why It Is Used

Methotrexate is used to treat severe psoriasis (more than 20% of the skin is affected) when creams, ointments, tar products, and phototherapy have not worked or cannot be used. It is also used to treat psoriatic arthritis.

Methotrexate cannot be used by women who are pregnant or trying to become pregnant or by people:

• With blood disorders or severe anemia.
• With stomach ulcers.
• With liver or kidney diseases.
• With an infectious disease, such as tuberculosis.
• Who drink alcohol frequently.
• Who cannot return to the doctor for tests to check for side effects of the medicine.

How Well It Works

Methotrexate takes several weeks to show benefits. If side effects can be tolerated, methotrexate can work very well for some people. If you are taking methotrexate, your blood tests should be monitored carefully. And it is very important that you do not drink alcohol.

Side Effects

Common temporary side effects include:

• Nausea, fatigue, loss of appetite.
• Trouble sleeping.
• Reduced white blood cell count.

Less common temporary side effects include:

• Sunburn if you are exposed to large doses of sunlight or ultraviolet (UV) light either before or after taking the drug.
• Vomiting, diarrhea, and occasional blood in the stools.
• Mouth sores.
• Easy bruising and bleeding.
• Skin rash or sores.
• Headaches.
• Chills and fever.
• Lightheadedness.
• Birth defects (if taken by a woman who is pregnant or who becomes pregnant while taking the medicine).

Long-term side effects include liver damage. If it is not severe, the damage reverses after you stop taking methotrexate. The risk of liver damage is higher if you drink a lot of alcohol, have kidney or liver problems or diabetes, or are overweight.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Because it can cause serious side effects, methotrexate is used only to treat severe psoriasis that cannot be treated with other medicines, such as psoriasis associated with arthritis (psoriatic arthritis).

People taking methotrexate need to have their blood counts and liver function tested before they start taking the drug and then regularly while they are taking it.

You may need to have a liver biopsy to check on the health of your liver while you are taking methotrexate.

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.

References

Citations

1. Abel E, Lebwohl M (2008). Psoriasis. In EG Nabel, ed., ACP Medicine, section 2, chap. 3. Hamilton, ON: BC Decker.