What is Methotrexate, and what is it meant to do? 

Methotrexate is in a class of drugs known as Disease Modifying Anti Rheumatic Drugs (DMARDs). It is used to treat inflammatory conditions such as Rheumatoid Arthritis, Psoriatic Arthritis, Systemic Lupus Erythematosus (SLE or Lupus), Ankylosing Spondylitis, Juvenile Idiopathic Arthritis and Crohn’s Disease. These conditions are autoimmune diseases because they are related to an “overactive” immune system.  

Methotrexate is an immunosuppressive medicine, which means it interrupts the activity of your immune system to prevent it from being “overactive”, slowing the disease and reducing inflammation. It not only regulates the immune system but protects the joints from damage and reduces the risk of long-term disability, hence the name “Disease-modifying”. 

Precautions Before Taking Methotrexate 

• Are you pregnant or planning to have children in the future? 
• Are you breastfeeding? 
• Do you have stomach problems, including a stomach ulcer? 
• Do you have problems with your liver or kidney? 
• Have you recently had or been in contact with people with chickenpox or shingles? 
• Are you taking any other medicines?  Including any medicines you buy without a prescription, such as herbal and complementary medicines and medicines for pain relief. 

If you answered yes to any of the precautions above, it’s essential that you tell your doctor or pharmacist before you start Methotrexate. Sometimes a medicine isn’t suitable for a person with certain conditions, or it needs to be used with extra care. 

Possible Interactions With Methotrexate

• Methotrexate may interact with several medicines and herbal supplements, so check with your doctor or pharmacist before starting Methotrexate and before starting any new medication.  
• Also, check with a pharmacist before taking over-the-counter anti-inflammatories such as diclofenac (e.g., Voltaren Rapid), ibuprofen (e.g., Nurofen), naproxen (e.g., Naprogesic). Taking these together with Methotrexate may cause side effects. 

How do I know Methotrexate is working? 

Keep taking Methotrexate regularly. Methotrexate does not work straight away. It usually takes a few weeks or months before you notice the full benefits. The Auckland Rheumatology and Sports Medicine Association says that it normally takes 3 months to notice the benefit from Methotrexate and up to 6 months for the peak effect. The Sandoz injection datasheet says it takes 4-8 weeks before you can notice benefits. If you stop methotrexate treatment for more than a few weeks, there is a risk that your condition may worsen.

Methotrexate Tablet or Injection? 

Methotrexate is usually taken in tablet form oncea week. It may be taken with or after food. The tablets should be swallowed whole and not crushed or chewed. The tablets come in two sizes; 10 mg and 2.5 mg. You should take the right dosage once a week. Accidentally taking too much can result in severe toxicity. Your doctor will advise you about what dose you should take. You will usually start on a low dose (e.g. 5 mg (2 tablets) or 7.5 mg (3 tablets) a week), which may be increased by your doctor if necessary. 

A 5 mg tablet of the vitamin folic acid is taken weekly four days after taking Methotrexate. This helps to prevent side effects. To help you remember to take your meds correctly, a simple alliteration tactic is used; “Methotrexate Monday; Folic acid Friday”. 

A once-weekly injection may be tried if the oral treatment causes too many gastrointestinal side effects. 

The recommended initial dose in injection form is 7.5 mg, once weekly. Depending on how your condition responds to the medicine and how you are tolerating it, the dose may be increased gradually by 2.5 mg per week, never exceeding 25mg/week. 

If changing from the tablet to the injection, a dose reduction may be required due to the variable bioavailability of Methotrexate after being taken in tablet form. 

Ask your prescriber and pharmacist as much as you can about this medication. They will have the most in-depth and relevant information for you and your situation. For more general information, see the links below: 

New Zealand Data Sheet – tradename (active ingredient) (medsafe.govt.nz) 

Methotrexate-Patient-Guide-RheumInfo_EN.pdf 

Methotrexate | Health Navigator NZ  

This information was reviewed by Graeme Blanchard, Community Pharmacist, Waitangirua Pharmacy.