This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anti-Cancer, Subject name: Pharmacology
[{'content': 'Folinic acid used in: \nSelect and explain. \nA. Methotrexate toxicity, B. Cisplatin toxicity, C. Vincristine toxicity, D. 5FU toxicity', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 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.', 'role': 'assistant'}]