Methotrexate Side Effects

What is Methotrexate?

Methotrexate is a medication prescribed to treat certain types of cancer, rheumatoid and psoriatic arthritis and other autoimmune diseases. It was previously known as amethopterin and it belongs to a group of drugs called antimetabolites. [1, 2, 3]

METHOTREXATE side effects

Methotrexate was made in 1947 and was first used to treat cancer. It blocks an enzyme that’s needed by cells to live, therefore affecting the growth of cancer cells, which the body destroys eventually. For arthritis and psoriasis, it improves the immune system. Methotrexate is also available under several brand names including:

  • Xatmep
  • Rheumatrex Dose Pack
  • Trexall
  • Otrexup
  • Rasuvo


Methotrexate is effective and widely used in the treatment of the following conditions:[1, 2, 3]

  • This drug is used in the treatment of certain types of cancer including leukemia, osteosarcoma, lung cancer, breast cancer, lymphoma, and bladder.
  • Methotrexate is used as a disease-modifying treatment for some autoimmune disease including Crohn’s disease, psoriasis, rheumatoid arthritis, lupus, eczema, sarcoidosis and juvenile dermatomyositis.
  • It is also used for ectopic pregnancy where the fallopian tube has not ruptured.
  • It may also be used for medical abortions. It is used in combination with misoprostol to terminate pregnancies in their early stages


An average dosage guideline for taking Methotrexate include:[2, 3, 4]

  • The dosage for cancer in adults depends on their weight and the type of cancer. Your doctor should determine your dose. A dose of 3.3-30mg once daily may be administered for a few days.
  • For rheumatoid or juvenile arthritis, the starting dose is 7.5mg or 2.5mg every 12 hours in 3 doses once weekly.
  • For psoriasis, the initial dose is 10-25mg once weekly.
  • The dose for children depends on their weight and the condition being treated. Their dose and use must be determined by a doctor.

Methotrexate Side Effects

Side effects of Methotrexate can be mild or severe depending on the amount of dose being taken. Common side effects of Methotrexate include:[2, 3, 5, 6, 7, 8, 9]

  • Nausea
  • Stomach pain
  • Dizziness
  • Vomiting
  • Blurred vision
  • Drowsiness
  • Tired feeling
  • Inflammation of the mouth and lips
  • Bleeding gums
  • Headaches

Allergic reaction

Though uncommon, Methotrexate may cause serious side effects. A very serious allergic reaction to this medication is also uncommon but ensure to contact your doctor immediately you notice any signs of severe allergic reaction including hives, swelling of the throat, face or tongue, itching, rash, breathing problems, and severe dizziness.

Other serious side effects

Other serious side effects of Methotrexate include:

  • Diarrhea
  • Blood in your urine or stools
  • Dry cough
  • Chills or fever
  • Shortness of breath
  • Yellowing of the eyes or skin (jaundice)
  • Weakness
  • Body aches
  • Clay-colored stools
  • Pale skin
  • Flu symptoms
  • Abdominal pain
  • Dark urine
  • White patches or sores inside your mouth or on your lips
  • A sore throat and headache with a severe peeling, blistering, or red skin rash
  • Difficulty urinating or less than usual
  • Loss of appetite
  • Easy bruising or bleeding
  • Impaired speech
  • Stiff neck
  • Sore eyes

Overdose side effects

If methotrexate is taken as prescribed by a doctor or health provider, it’s unlikely for an overdose to happen. However, if you happen to take excess, immediately contact your doctor or local Poison Control Center. Overdose side effects include:

  • Gastrointestinal bleeding
  • Nausea
  • Diarrhea
  • Vomiting
  • Severe bone marrow suppression
  • Liver function disturbance
  • Pale skin
  • Unusual weakness
  • Easy bruising or bleeding
  • Black or bloody stools
  • Mouth sores
  • Coughing up blood or vomit that looks like coffee grounds
  • Decreased urine output or not urinating at all

Adverse side effects

Not every patient who takes Methotrexate experiences side effects but it isn’t rare for adverse side effects to occur.This would require immediate medical attention if they occur. The adverse side effects of Methotrexate include:

  • This drug may cause a decrease in the number of blood cells made by your bone marrow. This can increase your chances of having an infection or bleeding. To avoid adverse effects, inform your doctor if you have or had any problem with your blood cells or a low number of any type of blood cells.
  • Long-term use of Methotrexate can lead to liver damage. Doctors may advise people who had taken or drink a lot of alcohol or with liver disease not to use this medication because they’re at a higher risk of developing liver damage. An exception can be made only if you have a life-threatening form of cancer. The risk is also higher in elderly patients.
  • Pregnant women should not use this drug because it can cause harm to the unborn baby. If the father uses Methotrexate and his sexual partner conceives, it could also lead to birth defects. Contact your doctor if you get pregnant while on Methotrexate.
  • Some men and women who use methotrexate have reported infertility cases. In the case that you’re planning to get pregnant, ensure to consult with your doctor before you start using this drug.
  • When Methotrexate is used in combination with radiation therapy it may increase the risk of bone or tissue problems including bone or tissue getting insufficient blood.
  • Methotrexate may also make your skin sensitive to ultraviolet light. People who have psoriasis and are taking Methotrexate their sores may worsen if their skin is exposed to sunlight.
  • This medication may also cause severe dizziness or drowsiness and this can be dangerous if you’re driving or operating machinery, therefore it’s crucial to avoid doing tasks that require you to be alert until you know how Methotrexate affects you.
  • Some people who take Methotrexate have experienced lung inflammation which causes breathing difficulties. This condition can be serious and at times life-threatening. While on Methotrexate if you experience new or worsening breath shortness or a non productive cough with or without fever, get an immediate medical checkup.
  • Methotrexate can metamorphose in breast milk and cause harm to a nursing baby. Mothers who are breastfeeding must avoid using this medication to prevent any adverse effects on the baby.
  • This drug can worsen kidney function and may even cause kidney failure. People with kidney disorders should not use Methotrexate without a doctor’s prescription. Elderly people are also at a higher risk of having severe side effects. This is because their kidneys may not work as well as they used to, hence causing the drug to accumulate in their body because their body process Methotrexate more slowly. Excess levels of Methotrexate in the body can be dangerous.

Reference List

  9. Methotrexate side effects available at

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