Methotrexate, sold under the brand name Methoblastin, is an antifolate drug, which means it inhibits the activation of folic acid in the body.It is taken once per week to treat a range of conditions. These include rheumatoid arthritis, the skin disorder psoriasis and inflammatory bowel disease. This weekly therapy is known as “low-dose methotrexate”.Methotrexate was first developed in the 1950s as a cancer treatment and is still used for this in higher doses.
How it works
The methotrexate drug molecule is structurally similar to folic acid, which is important for making new cells. It inhibits the enzyme (dihydrofolate reductase) that turns folic acid into its active form. This reduces cell growth and is why methotrexate is used to treat some cancers.The way methotrexate works for inflammatory conditions is less clear. But we know it has a range of effects on DNA synthesis and immune signalling, which are thought to reduce the inflammation.