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Vitamin B group (folate)

Folic Acid

Brand names: Folic Acid, Lexpec

Folic acid is a synthetic form of vitamin B9 used to treat and prevent folate-deficiency anaemia and to reduce the risk of neural tube defects in pregnancy.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It is reduced to tetrahydrofolate, an essential cofactor for single-carbon transfer reactions underpinning purine and pyrimidine synthesis, DNA replication and normal cell division.

Prescribing in practice

  • Giving folic acid in unrecognised vitamin B12 deficiency can improve the blood picture while permitting irreversible neurological damage, so exclude or treat B12 deficiency first in macrocytic anaemia.
  • Preconception and early-pregnancy supplementation reduces neural tube defect risk, with higher doses for women at increased risk.
  • Folate alone does not treat the underlying defect in pernicious anaemia.

Monitoring

Confirm response with a full blood count and assess vitamin B12 status before treating a macrocytic anaemia with folate.

Counselling the patient

  • Begin folic acid before pregnancy where possible and continue through early pregnancy.
  • Continue taking it as directed even when you feel well.
  • Mention any concern about low vitamin B12 to your clinician.

Evidence & guidelines

NICE advises folic acid in the periconceptional period to lower neural tube defect risk, with increased doses for higher-risk pregnancies.

Reference: NICE PH11 Folic Acid; RCOG Green-Top; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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