Methotrexate interferes with the growth of certain cells of the body, especially cells that reproduce quickly, such as cancer cells, bone marrow cells, and skin cells.

Methotrexate injection is used to treat leukemia and certain types of cancer of the breast, skin, head and neck, or lung. Methotrexate injection is also used to treat severe psoriasis and rheumatoid arthritis.

Methotrexate injection is usually given after other medications have been tried without successful treatment of symptoms.

Methotrexate injection may also be used for purposes not listed in this medication guide.

Methotrexate can harm an unborn baby or cause birth defects. Do not use if you are pregnant. Use birth control to prevent pregnancy while you are receiving methotrexate injection, whether you are a man or a woman. Methotrexate injection use by either parent may cause birth defects.

Methotrexate injection can cause serious or life-threatening side effects on your liver, lungs, kidneys, and bone marrow (immune system). To check for harmful effects, your blood will need to be tested often. Your kidney or liver function may also need to be tested, and you may need an occasional liver biopsy or chest x-ray. Visit your doctor regularly.

You may not be able to receive methotrexate injection if you have liver disease (especially if caused by alcoholism), a blood cell or bone marrow disorder, or if you are breast-feeding a baby. Your doctor will decide if this treatment is right for you.

There are many other drugs that can interact with methotrexate. Tell your doctor about all medications you use.

You should not use this medication if you are allergic to methotrexate (Rheumatrex, Trexall). Do not use methotrexate injection to treat psoriasis or rheumatoid arthritis if you have:

• chronic liver disease;

• alcoholism or cirrhosis of the liver;

• a blood cell disorder such as anemia (lack of red blood cells) or leukopenia (lack of white blood cells);

• a weak immune system or bone marrow disorder; or

• if you are pregnant or breast-feeding.

Methotrexate injection is sometimes used to treat cancer even when patients do have one of the conditions listed above. Your doctor will decide if this treatment is right for you.

To make sure you can safely use methotrexate, tell your doctor if you have any of these other conditions:

• kidney disease;

• liver problems;

• lung disease or pneumonia;

• stomach ulcer, ulcerative colitis;

• any type of infection; or

• if you are receiving phototherapy or radiation treatments.

FDA pregnancy category X. This medication can harm an unborn baby or cause birth defects. Do not use methotrexate if you are pregnant. Tell your doctor right away if you become pregnant during treatment.

Use birth control to prevent pregnancy while you are receiving methotrexate injection, whether you are a man or a woman. Methotrexate injection use by either parent may cause birth defects.

If you are a man, use a condom to keep from causing a pregnancy while you are receiving methotrexate injection. Continue using condoms for at least 90 days after your treatment ends.

If you are a woman, use an effective form of birth control while you are receiving methotrexate injection, and for at least one cycle of ovulation after your treatment ends.

Methotrexate can pass into breast milk and may harm a nursing baby. Do not breast-feed while you are using methotrexate.