Folinic Acid Dosing Guidelines for Children

Introduction to Folinic Acid Therapy

The American Academy of Dermatology recommends folinic acid (leucovorin) 1 mg daily (or 6 days per week, sparing the methotrexate administration day) for children receiving methotrexate therapy, as this dosing regimen decreases gastrointestinal intolerance and hepatic adverse effects better than once-weekly dosing 1, 2

For inflammatory skin diseases including psoriasis, atopic dermatitis, and other dermatologic conditions, the standard dose of 1 mg daily is recommended during methotrexate treatment 1, 2
Daily dosing (or 6 days per week) is superior to once-weekly dosing for reducing methotrexate-related adverse effects including gastrointestinal symptoms, oral mucositis, fatigue, and headache 1
The American Academy of Dermatology suggests continuing folinic acid throughout the entire duration of methotrexate therapy 1

For neonates and infants (first year of life), 10 mg orally three times weekly is recommended throughout the 12-month treatment course to prevent hematologic toxicity from pyrimethamine 3, 4

For dietary deficiency or chronic hemodialysis, 1-5 mg orally daily is recommended, and continue for 4 months or until the underlying cause is corrected 5

The Clinical Nutrition society advises evaluating for concomitant vitamin B12 deficiency before treating with folinic acid, as treating folate deficiency alone can worsen neurological manifestations of B12 deficiency 5
Measure folate status at first assessment in patients with macrocytic anemia or malnutrition risk, and repeat folate levels within 3 months after supplementation to verify normalization 5
Target serum folate ≥10 nmol/L and red blood cell folate ≥340 nmol/L 5

With methotrexate, perform laboratory monitoring at least 4-6 days after methotrexate dosing to avoid detecting transient transaminase elevations 2

The American Academy of Pediatrics recommends folinic acid dosing for a 13-year-old depends on the clinical indication, with 10 mg three times weekly for congenital toxoplasmosis treatment, 20 mg/m² every 6 hours for 24 days for methotrexate rescue in severe Pneumocystis pneumonia, and starting at 0.5-1 mg/kg/day with potential escalation to 2-3 mg/kg/day based on CSF monitoring for cerebral folate deficiency 6, 7

For toxoplasmosis treatment, the standard dose is 10 mg orally three times weekly throughout the treatment course, as recommended by the Centers for Disease Control and Prevention 6
Folinic acid is given as adjunctive therapy alongside pyrimethamine and sulfadiazine to prevent hematologic toxicity from pyrimethamine, with a strength of evidence level of high 6
For methotrexate rescue in severe Pneumocystis pneumonia, the dose is 20 mg/m² every 6 hours for 24 days when used with trimetrexate glucuronate, as recommended by the Centers for Disease Control and Prevention 7, 8

Oral administration is preferred for most indications, including toxoplasmosis and cerebral folate deficiency, as recommended by the American Academy of Pediatrics 6
Intravenous administration is required for methotrexate rescue protocols and may be necessary for severe cerebral folate deficiency with inadequate oral response, with a strength of evidence level of moderate 7

The Centers for Disease Control and Prevention recommends monitoring complete blood counts weekly during pyrimethamine therapy to assess for bone marrow suppression despite leucovorin supplementation, with a strength of evidence level of high 6
Do not discontinue leucovorin prematurely in methotrexate rescue protocols; it must extend beyond the antifolate therapy, as recommended by the Centers for Disease Control and Prevention 7