FAQ: Methotrexate

Why is this medication being recommended?

Methotrexate is part of a class of drugs called immunosuppressants. It suppresses the body's immune response and reduces inflammation in your lungs. Because inflammation is the precursor to fibrosis (scarring), we hope methotrexate will prevent the formation of lung fibrosis and allow the inflamed lung to return to normal.

What special precautions should I follow?

Before taking methotrexate:

  • Tell your doctor and pharmacist if you are allergic to methotrexate, any other medications or any of the inactive ingredients in methotrexate tablets. Ask your pharmacist for a list of the inactive ingredients.
  • Tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements and herbal products you are taking or plan to take. Be sure to mention those listed in the important warning section of the medication insert, as well as any of the following:
    • Certain antibiotics such as chloramphenicol (Chloramycetin), penicillins, and tetracycyline (Bristacycline, Sumycin)
    • Folic acid
    • Rheumatoid arthritis medications
    • Phenytoin (Dilantin)
    • Probenecid (Benemid)
    • Sulfonamides such as co-trimoxazole (Bactrim, Septra), sulfadiazine, sulfamethizole (Urobiotic), and sulfisoxazole (Gantrisin)
    • Theopylline (Theochron, Theolair)

    Your doctor may need to change the doses of your medication or monitor you more carefully for side effects.

  • Methotrexate may cause liver damage. Tell your doctor if you drink or have ever drunk large amounts of alcohol, or if you have or have ever had liver disease. Do not drink alcohol while you are taking methotrexate. Call your doctor immediately if you experience any of the following symptoms: nausea, extreme tiredness, lack of energy, loss of appetite, pain in the upper right part of the stomach, flu-like symptoms or yellowing of the skin or eyes.
  • Methotrexate may cause kidney damage. Be sure to drink plenty of fluids during your treatment with methotrexate, especially if you exercise or are physically active. Call your doctor if you think you might be dehydrated. You may become dehydrated if you sweat excessively or if you vomit, have diarrhea or have a fever.
  • Methotrexate may cause a decrease in the number of blood cells made by your bone marrow. Tell your doctor if you have, or have ever had, a low blood count (decrease in the number of blood cells in your body), anemia (red blood cells do not bring enough oxygen to all parts of the body), or any other problem with your blood cells.

    Call your doctor immediately if you experience any of the following symptoms:
    • Confusion
    • Difficulty falling asleep or staying asleep
    • Dizziness
    • Excessive tiredness
    • Fast heartbeat
    • Pale skin
    • Shortness of breath
    • Sore throat, chills, fever or other signs of infection
    • Unusual bruising or bleeding
    • Weakness
  • Methotrexate may cause a severe rash that can be life-threatening. If you develop a rash, blisters or a fever, call your doctor immediately.

  • Methotrexate may cause damage to your intestines. Tell your doctor if you have or have ever had stomach ulcers or ulcerative colitis, a condition in which part or all of the lining of the intestine is swollen or worn away. If you develop sores in your mouth or diarrhea, stop taking methotrexate and call your doctor immediately.

  • Tell your doctor if you are breast-feeding. You should not breast-feed during your treatment with methotrexate.

  • Before having surgery, including dental surgery, tell the doctor or dentist that you are taking methotrexate.

  • Methotrexate may make your skin sensitive to real or artificial sunlight. Avoid unnecessary or prolonged exposure to sunlight and wear protective clothing, sunglasses and sunscreen. Do not use sunlamps during your treatment with methotrexate. If you have psoriasis, your sores may get worse if you expose them to sunlight while taking methotrexate.

What side effects can this medication cause?

Methotrexate may cause side effects. Tell your doctor if any of the following symptoms are severe or do not go away:

  • Acne
  • Changes in skin color
  • Hair loss
  • Headache
  • Irregular menstrual periods
  • Swollen, tender gums

Some side effects can be serious. If you experience any of the following symptoms or any symptoms listed in the important warning section of the medication insert, call your doctor immediately:

  • Blood in urine
  • Blurred vision
  • Chest pain
  • Difficulty moving one or both sides of the body
  • Difficulty speaking or slurred speech
  • Fainting
  • Pain or redness of one leg only
  • Seizures
  • Sudden loss of vision
  • Urgent or frequent need to urinate
  • Weakness or numbness of an arm or leg

Methotrexate may cause other side effects. Tell your doctor if you have any unusual problems while you are taking this medication.

What monitoring will I need?

Your doctor will order regular lab tests to check your response to methotrexate and monitor for toxicity. You will need to have your blood counts — white blood cells, red blood cells and platelets — and liver function checked regularly. Your doctor may order additional tests depending on the results.

For additional information on methotrexate, please visit MedlinePlus.gov.


Reviewed by health care specialists at UCSF Medical Center.

This information is for educational purposes only and is not intended to replace the advice of your doctor or health care provider. We encourage you to discuss with your doctor any questions or concerns you may have.