Folinic acid

Folinic acid (BAN) or leucovorin (USAN), generally administered as the calcium or sodium salt (calcium folinate (INN), sodium folinate, leucovorin calcium, leucovorin sodium), is an adjuvant used in cancer chemotherapy involving the drug methotrexate. It is also used in synergistic combination with the chemotherapy agent 5-fluorouracil.

Folinic acid (also called 5-formyltetrahydrofolate) was first discovered in 1948 as citrovorum factor and occasionally is still called by that name. Folinic acid should be distinguished from folic acid (vitamin B₉). However, folinic acid is a vitamer for folic acid, and has the full vitamin activity of this vitamin. It is on the World Health Organization's List of Essential Medicines, a list of the most important medication needed in a basic health system.

Levofolinic acid and its salts are the 2S- form of the molecule. They are the only molecules that are biologically active.

Medical use

Folinic acid is administered at the appropriate time following methotrexate as part of a total chemotherapeutic plan, where it may "rescue" bone marrow and gastrointestinal mucosa cells from methotrexate. No apparent effect is seen on pre-existing methotrexate-induced nephrotoxicity. Folinic acid can be taken as a pill (orally) or injected into a vein (intravenously) or muscle (intramuscularly).