Leucovorin is used to decrease the toxicity of
Ref: Katzung 10th/887; KDT 6/e 823 Toxicity of methotrexate can be reversed by the administration of 5-formyltetrahydrofolate (leucovorin or citrovorum factor). Folic acid in the diet is in dihydrofolate form. It is ineffective in reversing methotrexate toxicity.
Methotrexate
6-Mercaptopurine
Thio-TEPA
Cytosine arabinoside
Chemotherapy