What role does Leucovorin play in methotrexate treatment?

Leucovorin plays a critical role in the treatment regimen involving methotrexate, particularly in reducing the harmful side effects associated with this chemotherapy agent. Methotrexate functions by inhibiting dihydrofolate reductase, which ultimately affects rapidly dividing cells, including cancer cells but also normal cells, leading to toxicity. Leucovorin, a form of folate, acts as a rescue agent. It bypasses the metabolic block caused by methotrexate and helps to replenish folate levels in normal cells, thereby mitigating the potential for serious adverse effects, particularly in tissues that rely heavily on folate for their rapid turnover, such as the gastrointestinal tract and bone marrow.

This protective effect of Leucovorin allows for higher doses of methotrexate to be used in treating certain cancers while decreasing the risk of significant toxicity. In situations like high-dose methotrexate therapy for conditions such as lymphomas, the administration of Leucovorin is vital to prevent severe myelosuppression and mucositis.

While enhancing the effect of methotrexate or acting as a pain reliever might seem beneficial, these roles do not define Leucovorin's primary function in this context. Likewise, while it can facilitate