Leucovorin (Folinic Acid) Administration in Children
Leucovorin dosing in pediatrics depends on the clinical indication and the methotrexate (MTX) regimen, with dosing individualized to MTX serum concentrations and renal function in the setting of high-dose MTX or MTX toxicity. [1]
Empiric leucovorin dosing without the MTX start time, MTX dose/route, and planned serum MTX monitoring interval is not appropriate. [1]
Indication-Dependent Dosing
Leucovorin is commonly administered as “rescue” after high-dose MTX therapy with timed initiation and MTX level–guided continuation. [1]
Leucovorin is also used for other folate-related indications, which require a different dosing approach than MTX rescue. [1]
Medication Selection Algorithm
For MTX rescue after high-dose MTX therapy, leucovorin should be selected to match the planned monitoring strategy and MTX concentration thresholds. [1]
In MTX rescue protocols, the route should be chosen based on ability to absorb the drug and to ensure reliable dosing. [1]
Treatment Initiation Timing
Leucovorin rescue after high-dose MTX therapy should be initiated 24 hours after the beginning of the MTX infusion. [1]
Standard Dosing Regimen for High-Dose MTX Rescue
Leucovorin rescue after high-dose MTX therapy should be administered as 15 mg (approximately 10 mg/m²) every 6 hours for 10 doses. [1]
Leucovorin doses should be administered by oral (PO), intramuscular (IM), or intravenous (IV) routes based on the product labeling and the ability to ensure consistent administration. [1]
St. Jude practice information describes leucovorin given every 6 hours for a total of 6 doses after high-dose MTX, with treatment adjusted based on MTX levels. [2]
MTX Level–Guided Dose Adjustment and Duration
Continuation and dose intensity should be adjusted using serum MTX concentrations and renal function changes. [1]
The FDA-labeled high-dose MTX rescue algorithm includes stopping/continuing criteria and escalation when MTX levels or creatinine indicate delayed clearance. [1]
Common Pitfalls to Avoid
Failure to initiate leucovorin at the protocol-specified time window after MTX is a major cause of preventable toxicity in MTX rescue strategies. [1]
Failure to adjust leucovorin dose based on serum MTX levels and renal function is a major cause of under-dosing during delayed MTX elimination. [1]
Practical Administration Constraints in Children
Leucovorin administration should be performed under the supervising oncology/pharmacy protocol that specifies MTX level sampling times and the leucovorin dose-change thresholds. [1]
When adherence to oral dosing is uncertain, IV or IM administration is supported by MTX rescue prescribing information to ensure reliable delivery. [1]