Folinic acid used in:

Ref: Goodman & Gillman's 13th ed. P 1177* Folic acid is an essential dietary factor which is converted to FH4 by DHFR enzyme and provide methyl groups for the synthesis of precursors of DNA.* Folic acid analogues such as MTX interfere with FH4 metabolism, thereby inhibiting DNA replication.* Adverse effects: Myelosuppression, GI toxicity.* Folinic acid (Leucovorin) can reverse toxic effects; used as "rescue" in high-dose therapy.* Glucarpidase, a methotrexate-cleaving enzyme, is approved to treat toxicity.