Ferrous fumarate
NHS information about the medicine ferrous fumarate, including what it’s used for, who can take it, how to take it, and side effects.
What is ferrous fumarate for
Ferrous fumarate is used to treat or prevent symptoms of iron deficiency anaemia, a condition caused by low iron levels.
How to take ferrous fumarate
Ferrous fumarate comes in different strengths, as tablets, capsules or liquid you swallow.
How and when you take it depends on if you’re taking it to treat or to prevent low iron levels.
You’ll usually take 1 tablet, capsule or liquid dose, once a day. If this causes side effects, you may need to take it on alternate days instead.
If you or your child are prescribed ferrous fumarate follow your doctor’s instructions about how and when to take it. They may want to check your iron levels after about 4 weeks.
If you buy ferrous fumarate from a pharmacy, follow the instructions that come with the pack.
It can take a couple of months for your iron levels to improve.
Always check the packet or leaflet that comes with your medicine.
When taking ferrous fumarate:
- try to take it at the same time each day
- take it with water or you can chew or crush some tablets – check with a doctor or pharmacist
- use the plastic syringe or spoon provided to take the liquid, do not use a spoon as it will not measure the right amount
- you can take it on an empty stomach, but if that causes stomach-related side effects, take it with food
Side effects of ferrous fumarate
Like all medicines, ferrous fumarate can cause side effects, but not everyone gets them.
Common side effects
Some side effects of ferrous fumarate include:
- diarrhoea or constipation
- stomach pain
- heartburn (indigestion)
- feeling sick
- darker than usual poo
Who can and cannot take ferrous fumarate
Most adults and children aged 12 years and older, can take ferrous fumarate. Children under 12 years old can take it if it's been prescribed by a doctor.
Ferrous fumarate is not suitable for everyone. You may not be able to take it if you have:
- anaemia that is not caused by low iron levels
- sickle cell disease or thalassaemia
- a stomach ulcer or stomach problems such as IBS (irritable bowel syndrome)
- regular blood transfusions
- been told that you have too much iron in your body
Breastfeeding and ferrous fumarate
You can usually take ferrous fumarate while breastfeeding, but check with a pharmacist or doctor first.
It's rare for breastfed babies to get any side effects from medicine you're taking, but speak to a healthcare professional if you have any concerns about your baby.
Pregnancy and ferrous fumarate
You can usually take ferrous fumarate if you’re pregnant, but check with a doctor first.
Find out more about ferrous fumarate for children on the Medicines for Children website.
Taking ferrous fumarate with other medicines, food and drink
There are some medicines that may affect how ferrous fumarate works.
These include:
- antibiotics such as doxycycline or ciprofloxacin
- indigestion medicines (antacids)
- medicines or herbal remedies containing magnesium calcium, zinc or other iron supplements
- levothyroxine, a medicine for thyroid gland conditions
These are not all the medicines that may affect your medicine.
Tell your doctor or a pharmacist about any other medicines, herbal remedies, vitamins or supplements you’re taking.
If you bought ferrous fumarate without a prescription, check the packet or leaflet that comes with the medicine.
Speak to a pharmacist or doctor if you're not sure you can take it.
Food and drink with ferrous fumarate
Taking ferrous fumarate with food may help with stomach-related side effects, but some food and drink can affect how the medicine works. These include tea, eggs or milk.
Find out more about your medicine
To find out more about your medicine, you can:
- check the leaflet that comes with it
- search for your medicine leaflet on the electronic medicines compendium website
- find out about ferrous fumarate for reflux in children on the Medicines for Children website
- speak to a pharmacist or doctor
