Methotrexate (MTX) is a drug used in the treatment of a variety of cancers, and autoimmune disorders such as asthma, psoriasis and rheumatoid arthritis. It is a nucleic acid anti-metabolite (like 6-MP), and a folic acid antagonist due to its similarity in structure. Specifically, it inhibits tetrahydrofolate dehydrogenase, which prevents the formation of tetrahydrofolate, necessary for synthesis of thymidylate, an essential component of DNA.
While considered a moderately toxic drug, it is widely used in combination therapy to reduce the does, and side effects, of any one drug. For example, small doses of methotrexate, smaller than those used for cancer, can considerably reduce the amount of systemic corticosteroids needed in severe asthma patients.
- MTX dihydrate
- Folex PFS
The most up-to-date information about Methotrexate and other drugs can be found at the following sites.