Parenteral methotrexate for the treatment of rheumatoid arthritis.

Methotrexate (MTX) is the anchor treatment for rheumatoid arthritis (RA) and has been very thoroughly studied in many different patient populations, as monotherapy and in combination with various other disease modifying antirheumatic drugs and biologic agents, as they became available. It has a well-established safety and efficacy profile and is the preferred first line agent for RA treatment. Historically, oral (PO) preparations of MTX have been used in the USA with minimal parenteral (subcutaneous, SC, and intramuscular, IM) administration. Several shortages of drug availability in a parenteral form have been possibly one of the reasons for this low level of use. Several studies have looked at the role of parenteral MTX in RA treatment, and these overall demonstrate better tolerability, bioavailability, and possible efficacy of MTX compared with PO preparation.