What is Methotrexate?
Methotrexate is a disease-modifying antirheumatic drug (DMARD) used to treat a range of inflammatory and autoimmune conditions, including rheumatoid arthritis, psoriatic arthritis, and psoriasis. It works by suppressing the overactive immune response that causes inflammation and joint damage in these conditions. Methotrexate is also used in cancer treatment at much higher doses.
How Does it Work for Arthritis?
In autoimmune conditions, methotrexate interferes with the production of cells involved in inflammation. It helps reduce joint inflammation, prevent joint damage, and improve physical function. It does not provide immediate pain relief — it typically takes 6–12 weeks to notice significant benefit.
How is it Taken?
For arthritis, methotrexate is usually taken once a week — this is crucial to remember, as taking it every day would be dangerous. It can be taken as a tablet or by injection. Folic acid (usually 5mg once a week, on a different day to methotrexate) is prescribed alongside it to reduce side effects.
Side Effects
- Nausea and stomach upset (often on the day of or after taking it)
- Mouth sores
- Fatigue
- Liver problems — regular blood tests to monitor liver function are required
- Lowered immunity — increased risk of infections
- Rare: lung problems (methotrexate pneumonitis)
Important Precautions
Methotrexate must not be taken during pregnancy or when trying to conceive (men and women). Regular blood tests are essential to monitor liver, kidney, and blood cell counts. Alcohol should be avoided or minimised. Vaccinations should be discussed with your doctor before taking live vaccines.