Methotrexate Injection USP is used alone or together with other medicines to treat several types of cancer, such as breast, head and neck, lung, blood, bone, lymph node, and uterus cancers.
Methotrexate Injection USP is also used to treat adults with severe rheumatoid arthritis and children with polyarticular juvenile idiopathic arthritis who had other treatments that did not work well. It is also used to control symptoms of severe psoriasis in adults who have not been helped by other treatments.
Methotrexate belongs to the group of medicines known as antineoplastics (cancer medicines). It blocks an enzyme that is needed by cells to live. This interferes with the growth of cancer cells, which are eventually destroyed by the body. For patients with arthritis or psoriasis, methotrexate may work by improving the immune system.