Methotrexate (MTX)

Generic name: Methotrexate.

Other brand names: Folex, Mexate, Rheumatrex.

Methotrexate is an antineoplastic and antipsoriatic. It slows cellular growth rate. 

Quick Facts About Methotrexate


Used to treat lymphoma and certain forms of leukemia. Also used to treat cancers of the uterus, breast lung, head, neck, and ovary. Used to treat rheumatoid arthritis and very severe psoriasis.

Methotrexate Dosage

Take exactly as prescribed. Is prescribed at high doses for cancer. After high-dose therapy, leuco-vorin may be prescribed to limit toxic effects of methotrexate.

  • Usual adult dose: dosage is specifically individualized to prevent under- or overdosage. When taking for psoriasis or rheumatoid arthritis, take once a week, not once a day — taking dosage on a daily basis can lead to fatal overdose.
  • Usual child dose: dosage is specifically individualized to prevent under- or overdosage.
  • Missed dose: skip missed dose and return to regular schedule. Do not double doses.

PILL Side Effects

Overdose symptoms:

lung or breathing problems, mouth ulcers, or diarrhea. Also, if you experience dry cough or fever, immediately inform your doctor. If you suspect an overdose, immediately seek medical attention.

May cause serious and fatal damage to liver, kidneys, bone marrow, lungs, or other parts of the body.

More common side effects: abdominal pain and upset, chills and fever, decreased resistance to infection, dizziness, fatigue, general feeling of illness, mouth ulcers, nausea. Side effects associated with taking methotrexate for psoriasis: burning sensation at psoriasis sites; hair loss and/or sun sensitivity.

Less common Methotrexate side effects: abortion, acne, anemia, birth defects, black or tarry stool, blurred vision, boils, bruises, changes in skin coloration, convulsions, diarrhea, drowsiness, fatigue, hair loss, headaches, hives, inability to speak, infection of hair follicles, infertility, inflammation of the gums or mouth, intestinal inflammation, kidney failure, loss of appetite, lung disease, menstrual problems, partial or complete paralysis, rash or itching, red patches on skin, sensitivity to light, sore throat, stomach and intestinal ulcers and bleeding, stomach pain, vaginal discharge, vomiting, vomiting blood. Rare side effects: diabetes, impotence, infection, joint pain, loss of sexual desire, muscular pain, osteoporosis, ringing in the ears, severe allergic reaction, shortness of breath, sleepiness, sudden death, sweating.


Do not take aspirin or other nonsteroidal painkillers (Advil or Naprosyn) while taking methotrexate for (high-dose) cancer therapy; can make this medication more toxic.

Inform your doctor before combining Methotrexate with the following medications, which may increase toxic effects:

cisplatin (Platinol), phenylbutazone (Butazolidin), phenytoin (Dilantin), probenecid (Benemid), sulfa medications such as Bactrim and Gantrisin. Certain antibiotics, such as Achromycin and chloramphenicol (Chloromycetin), and vitamin preparations containing folic acid may reduce effectiveness of this medication.

No known food/other substance interactions.

Special Cautions

Methotrexate causes birth defects and miscarriages. Must not be taken during pregnancy except in the case of cancer, where the potential benefit outweighs risk to fetus. For those wanting to conceive a child after methotrexate therapy, men should wait at least 3 months, and women should complete at least one menstrual cycle. Appears in breast milk; could affect a nursing infant.

Seniors are susceptible to the toxic effects from methotrexate.

Follow doctor’s instructions carefully for children.

  • Do not take if sensitive to or allergic to this medication.
  • Doctor should perform regular blood tests to monitor any serious damage to the body.
  • Inform your doctor of any new symptoms that develop during methotrexate therapy.
  • Should not be taken if you have psoriasis or rheumatoid arthritis and any of the following: abnormal blood count, cirrhosis of the liver or other chronic liver disease, alcoholism, anemia, immune-system deficiency.
  • Doctor should do a chest X-ray before starting this medication. If you experience cough or chest pain, chest X-ray will be repeated.
  • Doctor will prescribe with extreme caution if you have: active infection, liver disease, peptic ulcer, ulcerative colitis.

Note: provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Methotrexate side effects, please contact your healthcare provider.