Methotrexate

Common Name: methotrexate (for rheumatoid arthritis and psoriasis)

How does Methotrexate work?

Methotrexate belongs to the class of medications called disease modifying antirheumatic drugs (DMARDs). It is used to treat rheumatoid arthritis and psoriasis (a chronic skin disorder that produces patchy scales). It works by reducing the inflammation associated with rheumatoid arthritis and by attacking the rapidly-dividing cells that are involved in causing psoriasis. Your doctor may choose to use a medication for conditions other than the ones listed in these drug information articles. If you're unsure why you are taking this medication, contact your doctor.

How should I use Methotrexate?

Rheumatoid arthritis: The usual adult dose of methotrexate is 7.5 mg taken as one dose once weekly by mouth or 2.5 mg taken every 12 hours for three doses once weekly. Doses are sometimes adjusted gradually according to response but don't usually exceed 20 mg weekly. The benefits of treatment usually appear about three to six weeks after starting the medication. Psoriasis: The usual adult starting dose of methotrexate is 10 mg to 25 mg per week in one dose (tablet or injection) or 2.5 mg (tablet) taken every 12 hours for three doses once weekly. Doses can be adjusted gradually but don't usually exceed 30 mg weekly. Methotrexate may sometimes cause nausea. If you feel ill after taking methotrexate, do not stop taking the medication without first talking with your doctor. Your doctor or pharmacist may be able to help you with ideas to reduce the nausea associated with taking this medication. Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor. It is important that this medication be taken exactly as prescribed by the doctor. If you miss a dose, do not take the missed dose until you talk with your doctor. Do not double doses.

What form(s) does Methotrexate come in?

Methotrexate is available as round, yellow, scored tablets containing 2.5 mg methotrexate. The tablets should be protected from light. It is also available as an injectable solution in sterile vials of various sizes containing 10 mg or 25 mg of methotrexate per mL. The 10 mg/mL solution is available in a 2 mL vial; the 25 mg/mL solution is available in vials of 2 mL, 20 mL, 40 mL, and 200 mL. The solution should be stored at room temperature and protected from light.

What should I NOT take with Methotrexate?

Pregnancy: Methotrexate should not be taken by pregnant women with rheumatoid arthritis or psoriasis. Women who may be pregnant should not start methotrexate until they know for sure that they are not pregnant. Pregnancy should be avoided if either partner is taking methotrexate. Pregnancy should also be avoided for a minimum of three months after treatment for the male partner has finished and for at least one menstrual cycle after treatment for the female partner. Breast-feeding: Because of the potential for serious adverse reactions from methotrexate for breast-fed infants, it should not be used by nursing mothers. Medical conditions: People who have rheumatoid arthritis or psoriasis as well as alcoholism, alcoholic liver disease, or other chronic liver disease should not take methotrexate. People with rheumatoid arthritis or psoriasis who have immunodeficiency syndromes (e.g., HIV infection) should not take methotrexate. People with rheumatoid arthritis or psoriasis who have pre-existing blood disorders, such as significant anemia, should not take methotrexate. Allergy: Anyone with a known allergy to methotrexate or any of the ingredients of the medication should not take this medication.

Are there any other precautions or warnings for Methotrexate?

Kidney function: People with reduced kidney function should be monitored closely by their doctors while taking this medication. Lung problems: Consult your doctor at once if lung problems (especially a dry, non-productive cough) occur during treatment with methotrexate. Side effects: If you develop diarrhea, vomiting, or mouth sores while using this medication, tell your doctor at once. Skin rashes: If you develop any new skin rashes when taking this medication, report this to your doctor. Pregnancy: Methotrexate has been reported to cause miscarriages and birth defects. Pregnant women who have psoriasis or rheumatoid arthritis should not take methotrexate. Breast-feeding: Nursing mothers should not use methotrexate. Children: The safety and effectiveness of this medication have not been established for children with rheumatoid arthritis or psoriasis.