Leucovorin is used to decrease the toxicity of: (A) Methotrexate, (B) 6-Mercaptopurine, (C) Thio-TEPA, (D) Cytosine arabinoside
Answer is A. 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.