Methotrexate is a class or type of medication that is referred to as “antimetabolite” and “anti-folate drug“.

It is also known as MTX and was formerly called Amethopterin. It began in 1947 to treat cancer. In 1956, it help provide a cure to some forms of metastatic cancer. It is considered by the WHO as an “Essential Medication”.

It is most often used as an oral medication, that is given once a week. This is to reduce toxicity. It can also be administered through injection.

Monitoring through blood tests are recommended. Blood test for CBC, Liver Function, and Creatinine are recommended.

Method of Action:

1.) For cancer, methotrexate competitively inhibits DHFR (Dihydrofolate reductase), an enzyme that helps or participates in the synthesis of tetrahydrofolate.

2.) For the treatment of rheumatoid arthritis, inhibition of DHFR is not thought to be the main mechanism. The primary mechanisms seems to be the inhibition of enzymes involved in Purine Metabolism. This leads to excess Adenosine. The T cells activation is affect and this is believed to suppress intercellular adhesion molecule.

3.)  Another mechanism of MTX is the inhibition of the binding of Interleukin 1-beta to its cell surface receptor.

Overall, Methotrexate inhibits the production of Folic Acid.


–  Initially used as part of chemotherapy for cancer
–  Leukemia [acute lymphoblastic]
–  Other cancers
–  Early miscarriages
–  Ectopic Pregnancies
–  When added with misoprostol can terminate early pregnancies
–  Rheumatoid Arthritis
–  Psoriatic Arthritis
–  Psoriasis
–  Scleroderma
–  Ankylosing Spondyltis
–  Crohn’s Disease
–  Behcet’s disease
–  others

Side Effects

–  Nausea
–  Vomiting
–  Diarrhea
–  Hair loss
–  Headache
–  Rash
–  Abdominal pain
–  Abdominal pressure
–  Bloating
–  Anemia
–  Decreased white blood cells
–  many others

**** – Higher doses for cancer may have additional side effects along with those mentioned above

*** – Small amount of individuals may develop hepatitis

–  Adverse effects are potential when also taking penicillin

When not to take

–  Not to be taken during Pregnancy
–  Do not take if risk of becoming pregnant
–  Do not take if Lactating
–  Do not take If male and trying to get partner pregnant