Leucovorin rescue in methotrexate therapy serves to which of the following?

Leucovorin rescue in methotrexate therapy serves to which of the following?

• A. To enhance methotrexate efficacy
• B. To halt methotrexate action
• C. To measure serum concentration
• D. To reduce leucovorin side effects

Answer: (B)

Leucovorin rescue is about protecting normal cells from methotrexate toxicity. After high-dose methotrexate, folinic acid (leucovorin) is given to bypass the block in folate metabolism caused by MTX, replenishing the reduced folate pool in healthy cells so they can continue DNA synthesis and survive the treatment. This allows the therapy to be given at high MTX doses with a lower risk of harm to normal tissues. It does not aim to enhance methotrexate’s killing of cancer cells by stopping MTX action; in fact, timing is crucial—giving leucovorin too early or too aggressively can lessen the anti-tumor effect. It’s also not used to measure drug levels or to reduce leucovorin’s own side effects. The rescue thus serves to minimize toxicity while preserving the ability of methotrexate to work against the malignancy.

Leucovorin rescue is about protecting normal cells from methotrexate toxicity. After high-dose methotrexate, folinic acid (leucovorin) is given to bypass the block in folate metabolism caused by MTX, replenishing the reduced folate pool in healthy cells so they can continue DNA synthesis and survive the treatment. This allows the therapy to be given at high MTX doses with a lower risk of harm to normal tissues. It does not aim to enhance methotrexate’s killing of cancer cells by stopping MTX action; in fact, timing is crucial—giving leucovorin too early or too aggressively can lessen the anti-tumor effect. It’s also not used to measure drug levels or to reduce leucovorin’s own side effects. The rescue thus serves to minimize toxicity while preserving the ability of methotrexate to work against the malignancy.