Patient handout · Medications
Methotrexate is a medication that may be used to treat psoriasis or eczema, although it is also used to treat several other dermatologic conditions. It works by blocking an enzyme involved in the growth of cells. Methotrexate has been around since the 1950s. It was initially approved to treat certain types of cancer and is still used today. It was approved for use in psoriasis in the 1970s. The medication is relatively inexpensive and usually covered by insurance. Methotrexate is also effective for the treatment of psoriatic arthritis.
This is extremely important. If the medication is taken every day accidentally instead of every week, it can cause serious harm. Pick a day of the week you will most likely remember to take it. Blood tests are done frequently when the medication is first started, and the dose is usually changed depending on side effects and response. Methotrexate comes in 2.5 mg tablets, and the weekly dose is typically taken all at once or half in the morning and half in the evening of the same day. For example, if you take 15mg weekly (a typical dose), you would take all 6 tablets on the same day each week.
If you are trying to get pregnant, methotrexate is not the medication for you. If you are taking methotrexate and could get pregnant, you should be on hormonal birth control or an IUD to prevent this.
Other possible side effects include anemia, decreased white blood cell count, increased infection risk, hair loss, and diarrhea. If you are developing severe nausea or sores in your mouth, you must inform us of this. A small percentage of patients develop liver inflammation, and there is an increased risk of inflammation of the lungs. Folic acid is often taken to reduce the chance of these side effects. Because of the concern about liver toxicity, blood tests are ordered periodically. Patients who reach a cumulative dose of 3 g (which takes years) are usually advised to have a liver biopsy if they continue on the medication beyond that dose. Methotrexate also reduces the body's ability to fight off infections and may increase the risk of certain infections. There are multiple other possible adverse effects; a complete list of adverse effects is beyond the scope of this document but is listed in the package insert when you get your medication.
Individuals taking methotrexate are usually advised to keep their alcohol intake minimal.
Many other medications can be taken safely with methotrexate, but some should not be used with methotrexate. If you are prescribed a new medication, always mention taking methotrexate. One medication that should NEVER be used with methotrexate is sulfa-based antibiotics, such as Bactrim.
Appointments available at Hillside Medical Clinic in Victoria and Kensington Medical Clinic in Burnaby.