Methotrexate
![](/Images/godic/202501/27/Methotrexate_skeletal.svg1912.png")
![](/Images/godic/202501/27/Methotrexate_ball-and-stick_model1913.png")
![The coenzyme folic acid (top) and the anti-cancer drug methotrexate (bottom) are very similar in structure. As a result, methotrexate is a competitive inhibitor of many enzymes that use folates.](/Images/godic/202501/27/Methotrexate_vs_folate.svg1913.png")
![Methotrexate (green) complexed into the active site of DHFR (blue)](/Images/godic/202501/27/DHFR_methotrexate1913.jpg")
Methotrexate (MTX), formerly known as amethopterin, is an antimetabolite and antifolate drug.
It is used in treatment of cancer, autoimmune diseases, ectopic pregnancy, and for the induction of medical abortions. It acts by inhibiting the metabolism of folic acid via dihydrofolate reductase.