Vitamin B9 / folate supplement / hematopoietic · Antianemic, Nutritional Supplement
Also known as Folate, Vitamin B9, Pteroylmonoglutamic acid
KDIGO 2024 + manufacturer label
40 branded formulations and 249 fixed-dose combinations. Look up specific brands in the Drugs workspace.
Jan Aushadhi — generic available at GoI pharmacies
Essential cofactor for DNA synthesis, cell division, and amino acid metabolism. Converted to tetrahydrofolate (THF) and then to various coenzyme forms (5-methyl-THF, 10-formyl-THF) required for purine and pyrimidine synthesis, DNA methylation, and homocysteine remethylation to methionine
Essential in pregnancy; recommended 400-800 mcg/day preconception through first trimester to prevent neural tube defects
Excreted in breast milk; compatible with breastfeeding; recommended during lactation
While haematological parameters may improve, neurological defects associated with vitamin B12 deficiency may worsen or become irreversible.
Folic acid should never be given alone to patients with vitamin B12 deficiency. Vitamin B12 must be administered concurrently or prior to folic acid.
Source: KDT 7e · p610
Drug interaction classified as: synergy.
Source: DDInter
High-dose folic acid can correct the hematologic abnormalities of B12 deficiency while allowing irreversible neurologic damage (subacute combined degeneration) to progress unchecked.
Never treat megaloblastic anemia with folate alone without first ruling out B12 deficiency. Always check B12 and MMA levels before initiating folate therapy.
Source: Kimi deep-research + Cla
Drug interaction classified as: synergy.
Source: DDInter
Phenobarbitone can cause megaloblastic anaemia due to folate deficiency. Folic acid given in large doses can reduce the efficacy of phenobarbitone, increasing seizure risk.
Treat anticonvulsant-induced megaloblastic anaemia with folic acid, but avoid large doses to prevent antagonism of the anticonvulsant effect. Monitor folate levels and seizure control.
Source: KDT 7e · p610
Folic acid reduces methotrexate efficacy at high doses (competes for same transport); at low MTX doses (RA/psoriasis), folic acid reduces toxicity without reducing efficacy
For MTX in RA/psoriasis: give folic acid 5 mg weekly (24h after MTX). For cancer: avoid concurrent use during MTX therapy
Source: Kimi deep-research + Cla
May increase the frequency of seizures in susceptible children.
Be aware that large amounts of folic acid may counteract the antiepileptic effect of phenobarbital and increase the frequency of seizures.
Source: DDInter
Folic acid may reduce phenytoin levels and seizure control; phenytoin may increase folate requirements
Monitor phenytoin levels; may need dose adjustment
Source: Kimi deep-research + Cla
May increase the frequency of seizures in susceptible children.
Be aware that large amounts of folic acid may counteract the antiepileptic effect of primidone and increase the frequency of seizures.
Source: DDInter
Both affect folate metabolism; may have antagonistic effects at high folate doses
Monitor clinical response
Source: Kimi deep-research + Cla
2 additional low-confidence interactions hidden — those rows lack a documented mechanism or management plan in our sources.
Continue into a citation-backed clinical answer with the drug context already attached.
Sources: KD Tripathi 7e, Goodman & Gilman 14e, Harrison 22e, Katzung·Verified: 2026-05-19 · House clinical team·Cockpit curated: 2026-05-19