Methotrexate (formerly Amethopterin) is an antimetabolite used in the treatment of certain neoplastic diseases, severe psoriasis, and adult rheumatoid arthritis.
Chemically methotrexate is N-[4-[[(2,4-diamino-6-pteridinyl) methyl]methylamino]benzoyl]-L-glutamic acid.
The structural formula is:
Molecular weight: 454.45 C20H22N8O5
Methotrexate Injection, USP is sterile and non-pyrogenic and may be given by the intramuscular, intravenous or intra-arterial route. (See DOSAGE AND ADMINISTRATION.) The preserved formulation contains benzyl alcohol; do not use for intrathecal or high-dose therapy.
Methotrexate Injection, USP, Isotonic Liquid, Preservative Free, for single use only, is available in 25 mg/mL, 40 mL (1 g) vials.
Each 25 mg/mL, 40 mL vial contains methotrexate sodium equivalent to 1 g methotrexate and the following inactive ingredients: Sodium Chloride 0.490% w/v. Sodium Hydroxide and, if necessary, Hydrochloric Acid are added to adjust the pH to approximately 8.5.