Oral Methotrexate Therapy For Rheumatoid Arthritis

What you need to know including how it should be taken and the common side effects

Methotrexate has been around as a treatment option for rheumatoid arthritis since the early 1970s. It is still one of the most commonly  prescribed drugs for treating rheumatoid
arthritis today.

Rheumatologists agree that it is one of the safest drugs for managing the condition despite some reports to the contrary. The bottom line is to take the dose of methotrexate that  has been  tailored  for you, accompanied by periodic follow-up reviews with your treatment doctor.

What is it?

Methotrexate belongs to a class of drugs known  as disease-modifying anti-rheumatic drugs (DMARDs). These drugs curb the underlying disease process rather than simply treating the presenting symptoms. Methotrexate reduces the activity of the immune  system (your body’s defence system), which is overactive in rheumatoid arthritis and other forms of inflammatory arthritis.

How should it be taken?

Oral methotrexate comes in two strengths: 2.5mg and 10mg tablets. To avoid confusion, only one strength (usually 2.5mg tablets) is used.

Methotrexate is usually taken as a single weekly dose on the same day every week.  The recommended dose may be taken all at once or it may be divided into equal separate doses taken on the same day every week, if necessary.

Treatment is usually started with a very low dose of 5mg (two 2.5mg tablets)  or 10mg  (four 2.5mg tablets)  a week, increasing  to an average dose of 20mg  per week. The dose is adjusted by your doctor  depending on your response and it may be increased up to about 30mg  once a week. Therefore, additional visits may be required to the physician at the treatment onset to tailor the correct dose for you.

Things to discuss with your doctor before starting methotrexate

  • It is important to discuss any history of allergies to any medications, or an allergy to any of the ingredients in methotrexate tablets. Ask your doctor or pharmacist for a list of the ingredients.
  • Some antibiotics, vitamin supplements and other medications can interact  with methotrexate and may require  a dose adjustment to avoid serious side effects.  Therefore,  it is vital to discuss with your doctor and pharmacist your list of prescription and non-prescription medications including vitamins, nutritional supplements and herbal products which you are currently taking or plan to take.
  • If you have one or more of the following conditions, methotrexate may NOT be a suitable  treatment option  for you or you may require  a lower dose and close monitoring:
    • Folate (a type of B vitamin) deficiency
    • Blood cell or bone  marrow  disorder
    • Liver disorder  (especially, if caused  by excessive alcohol intake)
    • Kidney disease
    • Pneumonia or lung disease
    • Stomach ulcers
    • Any infection
    • If you are receiving radiation treatment

Common side effects and how to avoid them

The most common side effects associated with methotrexate are nausea, vomiting and diarrhoea. These can be avoided  by dividing the recommended  dose across the day instead of taking the tablets  all at once.  Taking the tablet  dose after meals is also best.

NOTE: The divided dose is to be consumed on the same day. For example if the day’s dose is divided into 2, take after breakfast and dinner.  Or if you divide it into 3, take each dose after every main meal if you have 3 meals per day.

Mouth ulcers and sores are other common side effects of methotrexate therapy. Many patients also complain of headaches, fatigue  and an overall ‘blah’ feeling, sometimes called ‘methotrexate fog’. This happens more so on the day after you take the dose.

A 5mg folate tablet  taken  the day after your Methotrexate dose is the recommended treatment to manage these side effects.  Folate tablets  in 5mg strength can be purchased over the counter in most pharmacies.

Serious side effects can be reduced to a minimum by following these important instructions:

  • Take the right dose,  as directed  by your doctor.
  • Take your dose of methotrexate on one day, once weekly, on the same day each week.
  • Complement the methotrexate dose by taking a 5mg folate tablet  on the next day.
  • Ensure that you follow up with your treating doctor as often as you need  to or as advised by the doctor.

Special precautions

  • Methotrexate should  NOT be taken  if you are pregnant or planning to get pregnant or breast-feeding.
  • Methotrexate may be temporarily  discontinued if you are having surgery, including dental surgery. Inform your surgeon or dentist  about the medication prior to the surgery.
  • Methotrexate sensitises your skin to sunlight. Avoid unnecessary or prolonged sun exposure and wear protective gear. If you have psoriasis, your sores may worsen if you expose your skin to sunlight while you are taking methotrexate.
  • Vaccinations,  especially live ones,  are not to be given while you are taking methotrexate. Discuss this with your doctor for safer options.

By Manu Arora
Project Coordinator
Arthritis & Osteoporosis NSW