WARNINGS - SEE BOXED WARNINGS.
For intrathecal and high-dose methotrexate therapy, use the preservative-free formulation of methotrexate. Do not use the preserved formulation of methotrexate for intrathecal or high dose therapy because it contains benzyl alcohol.
Use caution when administering high-dose methotrexate to patients receiving proton pump inhibitor (PPI) therapy. Case reports and published population pharmacokinetic studies suggest that concomitant use of some PPIs, such as omeprazole, esomeprazole, and pantoprazole, with methotrexate (primarily at high doses), may elevate and prolong serum levels of methotrexate and/or its metabolite hydroxymethotrexate, possibly leading to methotrexate toxicities. In two of these cases, delayed methotrexate elimination was observed when high-dose methotrexate was co-administered with PPIs, but was not observed when methotrexate was co-administered with ranitidine. However, no formal drug interaction studies of methotrexate with ranitidine have been conducted.
HANDLING AND DISPOSAL
Procedures for proper handling and disposal of anticancer drugs should be considered. Several guidelines on this subject have been published.1-7 There is no general agreement that all of the procedures recommended in the guidelines are necessary or appropriate.
DILUTION INSTRUCTIONS FOR LIQUID METHOTREXATE INJECTION PRODUCT
Methotrexate Injection USP, Isotonic Liquid, Contains Preservative
If desired, the solution may be further diluted with a compatible medium such as Sodium Chloride Injection, USP. Storage for 24 hours at a temperature of 21° to 25°C results in a product which is within 90% of label potency.