folic acid at a glance
Medicine class
B vitamin, also called vitamin B9.
Main roles
Prevents or treats folate deficiency and supports fetal neural-tube development.
Available forms
Tablets and oral solutions.
Food and driving
It can usually be taken with normal food and is not expected to impair driving.
What is folic acid used for?
Uses represented by selected UK products include:
Treating folate-deficient megaloblastic anaemia associated with poor nutrition, pregnancy, alcohol use, medicines or malabsorption.
Preventing folate deficiency associated with anticonvulsants, chronic haemolytic conditions or renal dialysis.
Folate support in haemolytic anaemias such as sickle-cell anaemia.
Preventing fetal neural-tube defects, including in pregnancies with recognised risk factors.
Folic acid is also commonly co-prescribed with low-dose methotrexate to reduce adverse effects; follow the methotrexate prescriber's instructions.
How does folic acid work?
The body converts folic acid into active folate coenzymes needed to make DNA building blocks and methionine, supporting cell division and normal red-blood-cell maturation.
folic acid preparations and strengths
Oral solution
Route: Oral
Strengths: 1 mg/mL, 2.5 mg/5 mL
Tablet
Route: Oral
Strengths: 5 mg
How to take folic acid
Take folic acid exactly as directed on the label or by the prescriber.
Swallow tablets whole with water.
Measure oral liquid with the supplied oral syringe or medicine spoon, not a household teaspoon.
Rinse reusable measuring equipment after use.
Check the leaflet because oral solutions differ in concentration, excipients and storage after opening.
folic acid side effects
Common or expected effects
- Nausea, reduced appetite, abdominal bloating and flatulence.
- Oral liquids may also cause diarrhoea, vomiting or an itchy rash.
Get urgent medical advice
- Seek urgent assessment for a widespread raised or itchy rash with facial or throat swelling, breathing difficulty, faintness or collapse.
folic acid in pregnancy
Adequate folate around conception and early pregnancy reduces the risk of neural-tube defects. People with relevant medical conditions, family or pregnancy histories, or medicines such as antiepileptics should ask their GP, midwife or specialist which preparation is appropriate.
folic acid while breastfeeding
Folic acid passes into breast milk but has not been associated with adverse effects in breastfed infants in the selected product information. It can usually be used while breastfeeding; check with a pharmacist or prescriber if taking a prescribed product or other medicines.
folic acid interactions
Tell the prescriber or pharmacist about all medicines and supplements. Relevant interactions include:
Phenytoin, phenobarbital, primidone and other antiepileptics
Correcting folate deficiency can lower some antiepileptic concentrations and reduce seizure control; review or monitoring may be needed.
Methotrexate
Folic acid can alter methotrexate's effects. When intentionally co-prescribed, follow the methotrexate clinician's instructions.
Common questions about folic acid
Answers are fully visible for fast scanning and source review.
Is folic acid the same as folate?
Folate is the vitamin naturally present in food and the body; folic acid is the manufactured form used in medicines and supplements.
Why should vitamin B12 be checked first?
Folic acid can improve blood-count changes while neurological damage from vitamin B12 deficiency continues, potentially delaying diagnosis.
More questions about folic acid
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.