Medivorin Injection (containing Leucovorin Calcium / Calcium Folinate IP, typically formulated as 50mg/5ml or 10mg/ml) is primarily used as a “rescue agent“ to prevent or treat the severe toxic side effects of high-dose methotrexate chemotherapy. It provides an active form of folate that bypasses the metabolic block caused by certain cancer drugs, protecting healthy tissue while allowing chemotherapy to work.