FPGEE NABP Practice Exam 2026 – Complete Prep Resource

Leucovorin calcium is the appropriate drug used to treat an overdose of methotrexate because it serves as a rescue medication in patients experiencing toxicity from this chemotherapy agent. Methotrexate is an antifolate medication that inhibits dihydrofolate reductase, thereby affecting the synthesis of DNA and RNA. When given in high doses for certain cancers, it can lead to toxicity, including myelosuppression and mucositis.

Leucovorin calcium is a form of folic acid that can bypass the metabolic block caused by methotrexate, allowing normal cells to resume their function and mitigate toxic effects. It helps replenish the folate levels in the body, counteracting the effects of methotrexate and promoting recovery of healthy cells, particularly in the bone marrow and gastrointestinal tract.

In contrast, the other options do not serve as effective treatments for methotrexate overdose. Acetylcysteine is primarily used as an antidote for acetaminophen toxicity, activated charcoal is utilized for various types of poisonings and overdoses but is less effective once methotrexate has been absorbed and metabolized, and flumazenil is used as a benzodiazepine antagonist, having no therapeutic role in methotre