To counteract the harmful effects of methotrexate, leucovorin is administered as a rescue therapy. Leucovorin acts as a reduced form of folic acid, bypassing the inhibition of DHFR and allowing for the continued synthesis of nucleic acids in healthy cells. This selective protection enables the cancer cells to be targeted by methotrexate while safeguarding normal cells from damage. It is crucial to administer leucovorin at the correct time and dose to achieve optimal protective effects.
