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Medications > Methotrexate > Methotrexate – Detailed Information

Methotrexate

What is Methotrexate?

Methotrexate is a Disease Modifying Anti-Rheumatic Drug (DMARD).  At higher doses, Methotrexate is used to treat cancer, but at much lower doses, it is used for the treatment of Rheumatoid arthritis, Psoriatic arthritis, and many other types of arthritis.  Occasionally doctors use Methotrexate for diseases other than arthritis.

How does Methotrexate work?

Methotrexate works by altering the body’s use of folic acid (a vitamin) which is needed for cell growth.  The exact way that methotrexate helps in arthritis is still unknown.

Why am I taking Methotrexate?

  • Your doctor has prescribed this medicine to help with the following:
  • Reduce the pain and swelling (inflammation) in your joints.
  • Improve your day to day function.
  • Delay any long-term damage from the joint inflammation.

What is the usual dose of Methotrexate?

  • Methotrexate can be taken by mouth (tablets) or by injection as follows:
  • Tablets: Methotrexate is available in 2.5 mg tablets.  The standard dose ranges from 6 tablets per week (15 mg) to 10 tablets per week (25 mg).
  • Injection: Methotrexate is available in a liquid (25 mg/mL) for injection.  The standard dose ranges from 0.6 mL (15 mg) to 1.0 mL (25 mg) per week.  Patients are usually taught to self-inject.

How often do I take Methotrexate?

Methotrexate is only taken ONCE A WEEK.  If Methotrexate is taken orally (tablets) the dose can be taken all at once or split up and taken twice over a 24 hour period.

Who should NOT take Methotrexate?

  • Patients who have had a previous reaction to methotrexate.
  • Women who are pregnant, planning on becoming pregnant, or are breast feeding.
  • Men who are planning pregnancy with their partner.
  • Some patients with diseases of the liver, kidney, or blood disorders.
  • Patients with active infections.

When will I start to feel the effects of Methotrexate?

Methotrexate does not work right away.  It can take about 2 to 8 weeks before you start feeling better.  The maximum effect can take up to 3 – 6 months.  If your doctor changes the dose it can take another 6 to 8 weeks before you feel the effects.

Why might my doctor tell me to take Folic Acid?

Folic acid is a vitamin that can help to reduce some of the side effects of the Methotrexate should they occur.

What should I Avoid while taking Methotrexate?

  • Use alcohol in moderation (1 drink per week or less).
  • Do not get pregnant.
  • Do not take antibiotics containing sulfa (Bactrim or Septra).

Which Medications are safe to take with Methotrexate?

Your rheumatologist may decide to add other medications to treat your arthritis.

It has been thought that Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) and Methotrexate should not be taken together but research has shown this combination to be quite safe.  Some of the other medications which may be safely added to Methotrexate include: Acetaminophen, Prednisone, Other DMARDs (i.e. Sulfasalazine, Hydroxychloroquine, and Gold), and Biologics (i.e. Etanercept, Infliximab, Anakinra).

What are the side-effects of Methotrexate?

The information sheets given by pharmacists do not distinguish between high and low dose Methotrexate.  Side effects seen which may be seen with low-dose Methotrexate include the following:

MORE COMMON side-effects include:

  • Nausea, indigestion, and diarrhea.
  • Sores in the mouth.
  • Feeling generally unwell after taking the Methotrexate.
  • Headaches & irritability

RARE side-effects include:

  • Hair loss (rare with low dose) and sensitivity to the sun (rare).
  • Liver – Methotrexate may irritate the liver.  This does not usually cause symptoms but may be found on blood tests.  It is uncommon and usually reversible when regularly monitored with your monthly blood tests.
  • Blood Counts – Methotrexate can cause a drop in the numbers of white blood cells (which are needed to fight infection) and platelets (which help to stop bleeding).  Because we monitor the blood count very closely, it is unusual for this to be a serious problem.
  • Lungs  – Methotrexate may irritate the lungs.  If you develop a cough, fever, or shortness of breath, STOP the Methotrexate and call your doctor immediately.
  • Infection – Any infections or fevers should be taken seriously and reviewed by your doctor.

How can I help to minimize the side-effects of Methotrexate?

  • Take your Methotrexate ONCE A WEEK as prescribed by your doctor.
  • Tablets can be split up and taken at two times over a 24 hour period (i.e. take them with breakfast and dinner).
  • Taking your Methotrexate before you go to bed can sometimes help as you may sleep through any nausea or general unwellness.
  • Taking folic acid may help to reduce the side effects of the methotrexate.
  • Some patients find switching from pills to injections helps to reduce side effects.

Do I need to have regular blood tests while taking Methotrexate?

You will need BLOOD TESTS EVERY 1 – 3 MONTHS.  This is important to make sure the methotrexate is having no harmful effects on your liver or blood counts.

How do I stop the Methotrexate?

You do not need to wean yourself off the Methotrexate.  It can simply be stopped.  However, your arthritis may “flare” after you stop the medicine.

Is Methotrexate safe in pregnancy?

  • Methotrexate may cause birth defects and result in miscarriage.  You should AVOID PREGNANCY while on Methotrexate.
  • All women of child bearing potential taking Methotrexate must use reliable contraception.  If you become pregnant while taking Methotrexate NOTIFY YOUR DOCTOR IMMEDIATELY.
  • Do not breast feed while taking methotrexate.