Folinic AcidRx

Trade Names: Lederle Leucovorin

Synonyms: Leucovorin calcium, citrovorum factor, tetrahydrofolate

Drug Class: Vitamin

Preparations
Injection: 10 mg/mL
Powder for injection: 50-, 100-, 200-, 350 mg
Tablets: 5-, 15-, 25 mg

Dose: After inadvertent overdose, or prolonged methotrexate concentrations in patients with renal failure, use folinic acid 10 mg/m2 i.v. every 6 h for 72 hours until MTX concentrations decrease to <1 x 10-8 mol/L. Alternatively, similar oral doses have been used in patients who had no nausea or vomiting. Extremely high concentrations of MTX require higher doses of folinic acid. (Dosing graphs are available in the package insert to further delineate dose.) Urine alkalinization and hydration are also often indicated. With routine MTX use, 5 mg folinic acid orally is given post-dose once a week to lessen side effects.

Indications: MTX toxicity

Mechanism of Action: Replaces the folinic acid whose synthesis is inhibited by MTX

Monitoring: In MTX overdose or toxicity, measurement of MTX concentrations is a useful guide to therapy and folinic acid dose.

Pregnancy Risk: C

Comments: Folinic acid has been used to prevent minor adverse effects owing to MTX, but the data supporting the use of folic acid are stronger, folic acid is cheaper, and there is theoretical concern that folinic acid may antagonize the anti-inflammatory effects of MTX.

Cost: $$

BIBLIOGRAPHY
Shea B, Swinden MV, Tanjong Ghogomu E, et al. Folic acid and folinic acid for reducing side effects in patients receiving methotrexate for rheumatoid arthritis. Cochrane Database Syst Rev. 2013 May 31;5:CD000951.PMID:23728635