Abstract

Leucovorin (LCV) acts as an essential coenzyme for nucleic acid synthesis and also it is an active metabolite of folic acid. LCV can be used to selectively “rescue” cells from the adverse effects of methotrexate (MTX). Here, we report a case of LCV-induced hypersensitivity reaction when used in combination with high dose MTX (HDMTX). We describe a 2-years- old female baby diagnosed with B-cell acute lymphoblastic leukemia on chemotherapy with pediatric berlin-frankfurt- munster protocol; she is on HDMTX and injection LCV. After initiation of LCV (folinic acid) at 42 h she was noted to have hypersensitivity reaction. Despite reaction to LCV is uncommon, one should be aware of the reactions that can be caused by LCV.