Folic acid - Common brands: Lexpec

What folic acid is for

Folic acid is a man-made (artificial) version of vitamin B9, which is also known as folate.

Folic acid is often used to:

• treat folate deficiency anaemia (a lack of folate)
• help a baby's brain, skull and spinal cord develop properly and reduce the risk of them getting serious conditions like spina bifida

Other uses of folic acid can include:

• stopping folate levels getting too low during dialysis (a procedure to remove waste products from the blood if your kidneys are not working properly)
• preventing side effects from methotrexate, a medicine used to treat severe Crohn's disease, rheumatoid arthritis and psoriasis

How to take folic acid

Folic acid usually comes as tablets or a liquid (oral solution). There are also tablets and capsules that combine folic acid with other vitamins and minerals (multivitamins).

How much you need to take and how you take it depends on which type it is, how much folic acid it contains and why you're taking it.

If you're pregnant you should take a folic acid supplement for the first 12 weeks of your pregnancy. If you're planning a pregnancy, you can start taking it before you get pregnant.

Some pregnant women need to take a higher dose than others, so check with a pharmacist, midwife or doctor if you're not sure.

If a doctor prescribes folic acid for you, follow their advice about how to take it and how much to take.

When taking folic acid:

• swallow tablets whole with a glass of water
• use the syringe or spoon that comes with liquid folic acid to measure out the right amount from the bottle

Always check the packet or leaflet that comes with your medicine. Ask a pharmacist or doctor for advice if you're not sure how to use it or have any problems using it.

If you miss a dose of folic acid

If you forget to take a dose of folic acid, take it as soon as you remember and then take the next dose at the usual time.

Do not take 2 doses to make up for a missed dose.

If you take too much folic acid

Taking an extra dose of folic acid on its own is unlikely to cause problems, but taking too many multivitamin tablets or capsules can be dangerous.

Side effects of folic acid

Like all medicines, folic acid can cause side effects, although not everyone gets them.

Possible side effects of folic acid tablets include:

• bloating
• farting (flatulence)
• feeling sick (nausea)
• loss of appetite

Liquid folic acid can also cause diarrhoea, vomiting and a skin rash that may be itchy.

Folic acid does not usually affect your ability to drive, ride a bike or use machinery.

Serious side effects

Rarely, folic acid can cause a more serious allergic reaction called anaphylaxis.

Symptoms can include a swollen face, throat or tongue, a raised, itchy rash and difficulty breathing.

Who can and cannot take folic acid

Most adults and children over 12 months can take folic acid on its own.

Multivitamins containing other vitamins combined with folic acid are not recommended for children under 12 years of age.

Folic acid is not suitable for everyone. For example, it may not be suitable if:

• you've had an allergic reaction to folic acid or another ingredient used in the medicine in the past
• you have vitamin B12 deficiency anaemia or pernicious anaemia (a condition where your immune system attacks your body's healthy cells)
• you have cancer

Before taking folic acid, tell your doctor if you have any medical conditions.

Breastfeeding and folic acid

Folic acid can usually be taken while breastfeeding, but check with a pharmacist or doctor first before taking it.

It's rare for breastfed babies to get any side effects of medicines you're using, but speak to a healthcare professional if you have any concerns about your baby.

Pregnancy and folic acid

Folic acid supplements are often taken during pregnancy, but ask your doctor or pharmacist for advice if you're unsure before taking them.

Some women need to take more than the usual recommended dose of folic acid while they're pregnant.

If you're pregnant, you should also check with a doctor or pharmacist before taking a multivitamin that contains folic acid.

Find out more about taking folic acid during pregnancy on the Bumps (Best Use of Medicines in Pregnancy) website

Taking folic acid with other medicines, herbal remedies and supplements

There are some medicines, remedies and supplements that may not mix well with folic acid.

These can include:

• epilepsy medicines, such as phenytoin, phenobarbital and primidone
• antibiotics, such as chloramphenicol and co-trimoxazole
• sulfasalazine, which is a medicine used to treat ulcerative colitis, Crohn's disease and rheumatoid arthritis
• lithium, a medicine used to treat mental health conditions
• aspirin used for pain relief or thinning your blood

Before taking folic acid, tell your doctor if you're taking any other medicines, herbal remedies, vitamins or supplements.

Food, drink and alcohol with folic acid

You can usually eat as normal while taking folic acid, but if you're taking it as part of a multivitamin there may be certain foods and drink you need to avoid.

Check the leaflet that comes with your medicine or ask your doctor or pharmacist if you're unsure.

It's best to avoid or limit alcohol because it can affect how well folic acid works.