ferrous sulfate at a glance
Medicine class
Oral iron replacement: a ferrous iron salt.
Main uses
Treatment of iron-deficiency anaemia and, for Ironorm Drops, prevention of iron deficiency anaemia.
Food
Absorption is generally best on an empty stomach, but taking it with or after food may reduce stomach upset.
Important safety point
Keep iron medicines securely out of children's sight and reach; accidental overdose can be fatal.
What is ferrous sulfate used for?
Selected UK products are licensed for:
Treatment of iron-deficiency anaemia.
Prevention of iron deficiency anaemia with Ironorm Drops.
How does ferrous sulfate work?
Ferrous sulfate supplies iron that the body uses to make haemoglobin, enabling red blood cells to carry oxygen.
ferrous sulfate preparations and strengths
Tablet
Route: Oral
Strengths: 200 mg
How to take ferrous sulfate
Follow the product label or prescriber's instructions. Administration differs between tablets and drops.
Swallow coated tablets whole with water. Do not suck, chew or hold them in the mouth because this may cause ulceration or tooth staining.
Iron is absorbed best on an empty stomach, but food may reduce stomach upset.
Tea, coffee, eggs and dairy products reduce absorption; avoid taking them at the same time.
Measure drops with the supplied oral syringe or dropper, not a kitchen teaspoon. Rinse the mouth afterwards to help limit tooth staining.
Tell a pharmacist or prescriber if tablets are difficult to swallow.
ferrous sulfate side effects
Common or expected effects
- Nausea or vomiting
- Abdominal discomfort or heartburn
- Constipation
- Diarrhoea
- Dark stools
- Reduced appetite
- Reversible tooth staining, particularly with drops
Get urgent medical advice
- Severe allergic reaction, including swelling, breathing difficulty or collapse
- Bronchospasm or an allergic reaction in someone sensitive to sodium metabisulfite in Ironorm Drops
- Red, bloody or tar-like stools, especially with other illness
- Mouth or upper gastrointestinal ulceration if a tablet is chewed, sucked, retained in the mouth or becomes lodged
ferrous sulfate in pregnancy
Ferrous sulfate can be used in pregnancy when tests show low iron. First-trimester use should follow confirmation of need and an individual benefit–risk assessment. Constipation and haemorrhoids may become more troublesome.
ferrous sulfate while breastfeeding
Ferrous sulfate can usually be taken while breastfeeding. Supplemental iron does not meaningfully increase the amount reaching the baby through breast milk; a baby with iron deficiency needs separate assessment and treatment.
ferrous sulfate interactions
Ferrous sulfate can affect the absorption of other medicines, while some medicines and foods reduce iron absorption. Ask a pharmacist how to separate them.
Tetracycline and quinolone antibiotics
Iron and these antibiotics can reduce each other's absorption.
Levothyroxine
Ferrous sulfate reduces levothyroxine absorption.
Antacids and calcium, magnesium or zinc supplements
These can reduce iron absorption; iron can also reduce zinc absorption.
Common questions about ferrous sulfate
Answers are fully visible for fast scanning and source review.
Why does ferrous sulfate make my stools dark?
Dark stools are an expected effect of oral iron and are usually harmless. Seek urgent advice for tar-like, red or bloody stools, particularly if you feel unwell.
Can I take ferrous sulfate with food?
It is generally absorbed better on an empty stomach, but food may help if it causes nausea or stomach discomfort.
Can ferrous sulfate tablets be chewed or crushed?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.