Methotrexate is used to treat leukemia and certain types of cancer of the breast, skin, head and neck, lung, or uterus.

Methotrexate is also used to treat severe psoriasis and rheumatoid arthritis in adults.

Methotrexate is also used to treat active polyarticular-course juvenile rheumatoid arthritis in children.

Methotrexate is sometimes given when other medicines have not been effective.

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

You should not use methotrexate if you are allergic to it. You may not be able to take methotrexate if you have:

• alcoholism, cirrhosis, or chronic liver disease;
• low blood cell counts;
• a weak immune system or bone marrow disorder; or
• if you are pregnant or breastfeeding.

Methotrexate is sometimes used to treat cancer in people who have a condition listed above. Your doctor will decide if this treatment is right for you.

Tell your doctor if you have ever had:

• liver problems, especially fluid in your stomach (ascites);
• kidney disease;
• lung problems, especially fluid in the lungs (pleural effusion);
• radiation treatments; or
• a stomach ulcer or ulcerative colitis.

Tell your doctor if you are pregnant or plan to become pregnant. Methotrexate may cause injury or death to an unborn baby and should not be used during pregnancy to treat arthritis or psoriasis. However, methotrexate is sometimes used to treat cancer during pregnancy.

Methotrexate can harm an unborn baby if the mother or the father is using this medicine.

• If you are a woman, you may need to have a negative pregnancy test before starting this treatment. Use effective birth control to prevent pregnancy while you are using methotrexate and for at least 6 months after your last dose.
• If you are a man, use effective birth control if your sex partner is able to get pregnant. Keep using birth control for at least 3 months after your last dose.
• Tell your doctor right away if a pregnancy occurs while either the mother or the father is using methotrexate.

This medicine may affect fertility (ability to have children) in both men and women. However, it is important to use birth control to prevent pregnancy because methotrexate may harm the baby if a pregnancy does occur.

Do not breastfeed while using this medicine, and for at least 1 week after your last dose.

Do not give this medicine to a child without the advice of a doctor.

Use Rheumatrex Dose Pack (Oral) exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning in your eyes, skin pain, red or purple skin rash that spreads and causes blistering and peeling).

Methotrexate can cause serious or fatal side effects. Call your doctor at once if you have:

• sudden chest pain, wheezing, dry cough, cough with mucus, chest pain, feeling short of breath;
• fever, chills, swollen lymph glands, night sweats, weight loss;
• blisters or ulcers in your mouth, red or swollen gums, trouble swallowing;
• vomiting, diarrhea, blood in your urine or stools;
• skin changes such as redness, warmth, swelling, or oozing;
• low blood cell counts--fever, chills, tiredness, mouth sores, skin sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed or short of breath;
• kidney problems--little or no urination, swelling in your feet or ankles;
• liver problems--swelling around your midsection, right-sided upper stomach pain, nausea, loss of appetite, dark urine, jaundice (yellowing of the skin or eyes);
• nerve problems--confusion, weakness, drowsiness, coordination problems, feeling irritable, headache, neck stiffness, vision problems, loss of movement in any part of your body, seizure; or
• signs of tumor cell breakdown--tiredness, weakness, muscle cramps, nausea, vomiting, diarrhea, fast or slow heart rate, tingling in your hands and feet or around your mouth.

Common side effects may include:

• fever, chills, tiredness, not feeling well;
• low blood cell counts;
• mouth sores;
• nausea, stomach pain;
• abnormal liver function tests;
• hair loss;
• burning skin lesions; or
• being more sensitive to light.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Avoid drinking alcohol. It may increase your risk of liver damage.

Do not receive a "live" vaccine while using methotrexate, or you could develop a serious infection. Live vaccines include measles, mumps, rubella (MMR), rotavirus, typhoid, yellow fever, varicella (chickenpox), zoster (shingles), and nasal flu (influenza) vaccine.

Methotrexate could make you sunburn more easily. Avoid sunlight or tanning beds. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.