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Reduced folate (active enantiomer of folinic acid)

Levofolinic acid (calcium levofolinate)

Brand names: Isovorin

Adult dose

Dose: Methotrexate rescue: 7.5mg every 6h until MTX <0.05 micromol/L. With 5-FU: per protocol

Route: PO/IV/IM

Frequency: per protocol

Clinical pearls

Pure active enantiomer — half the dose of racemic folinic acid
Methotrexate rescue, 5-FU potentiation

Contraindications

Pernicious anaemia or B12 deficiency

Side effects

Allergic reaction
GI upset

Interactions

Phenytoin (reduced effect at high doses)
5-FU (enhanced)

Monitoring

MTX level
FBC

Reference: BNF; UKHCDO; https://bnf.nice.org.uk/drugs/levofolinic-acid/. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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