Methotrexate inhibits nucleic acid synthesis by blocking the activation of folic acid. Leucovorin is folic acid in its active (reduced) form, so it allows nucleic acid synthesis to proceed even in the presence Ò€¦ The goal is to enhance the solubility and dilution of methotrexate in the urine and apply leucovorin rescue guided by serial serum methotrexate levels to protect against potentially lethal toxicity.

This document reflects what is currently regarded as safe practice. Preventing high-dose methotrexate toxicity requires effective methotrexate monitoring and knowledge of the appropriate protocols for leucovorin rescue and the role of glucarpidase, said katherine Ò€¦