Oral ferrous iron Pregnancy: Ferrous fumarate can be used during pregnancy if clinically indicated. Breastfeeding: no adverse effects have been shown in breastfed infants of treated mothers and it can be used during breast-feeding if clinically indicated.

Ferrous fumarate

Brand names: Galfer, Fersaday, Fersamal

Used in: Anaemia

Ferrous fumarate is an oral ferrous (iron[II]) salt used to treat and prevent iron-deficiency anaemia.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Treatment of iron deficiency: two 5 mL spoonfuls of syrup (2 x 140 mg ferrous fumarate, approximately 2 x 45 mg = 90 mg elemental iron) twice a day. Prevention of iron deficiency: one 5 mL spoonful (140 mg ferrous fumarate, approximately 45 mg elemental iron) twice a day.

Route: Oral

Frequency: Twice daily (both the treatment and the prevention regimen)

SOURCE PRODUCT: Ferrous fumarate 140 mg/5 mL syrup (Fersamal syrup) UK SPC — each 5 mL contains 140 mg ferrous fumarate, approximating to 45 mg of elemental iron. ELDERLY: as for adults. DURATION: medical advice should be sought if symptoms do not improve after four weeks of use, as they may reflect an underlying disease process; duration of treatment of uncomplicated iron deficiency anaemia should not usually exceed 6 months (3 months after reversal of the anaemia). ABSORPTION: some post-gastrectomy patients show poor absorption of iron. Care is required in patients with treated or controlled peptic ulceration. Because anaemia due to combined iron and vitamin B12 or folate deficiency may be microcytic, patients with microcytic anaemia resistant to iron alone should be screened for vitamin B12 or folate deficiency. EXCIPIENTS (syrup): long-term treatment may increase the risk of dental caries — maintain adequate dental hygiene; contains sugar (care in diabetes mellitus), glucose (avoid in glucose-galactose malabsorption) and sucrose (avoid in hereditary fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency). Keep out of the reach of children. PAEDIATRIC PREVENTION DOSES (age bands, not per kg — see paedDose for the treatment regimen): 6 to 24 months 12.5 mg/day; 2 to 5 years 20 to 30 mg/day; 6 to 11 years 30 to 60 mg/day; older children 60 mg/day. Premature infants: 5 mg elemental iron per day — iron supplementation in premature infants is only recommended in those of low birth weight who are solely breast fed; higher doses up to 2 mg/kg of elemental iron per day might be needed to cover the needs of growing exclusively breastfed infants; supplementation should be commenced 4 to 6 weeks after birth and continued until mixed feeding is established. Verify all paediatric use against a children's formulary.

Paediatric dose

Dose: 3 mg elemental iron/kg

Route: Oral

Frequency: Daily, given in 2 to 3 divided doses

Max: Total daily dose should not exceed 180 mg elemental iron

Treatment of iron deficiency in full term infants and children: 3 to 6 mg elemental iron/kg/day given in 2 to 3 divided doses (dosePerKg records the lower bound of the stated 3 to 6 mg/kg/day range). Administration to infants and children should take place under medical advice. Separate age-band PREVENTION doses are stated in the SPC and are not per-kg — see adultDose.notes. Verify against a children's formulary before prescribing.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Paediatric weight-based calculator

Patient weight (kg)

Verify in a children's formulary

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Paroxysmal nocturnal haemoglobinuria
Haemosiderosis, haemochromatosis
Active peptic ulcer
Repeated blood transfusions
Regional enteritis and ulcerative colitis
Must not be used in anaemias other than those due to iron deficiency

Side effects

Gastrointestinal irritation — nausea and epigastric pain (the commonest side effects)
Constipation or diarrhoea (reducing the dose or switching to an alternative iron salt may help)
Darkening of stools
Black discoloration of the teeth
Allergic reactions (due to metabisulphite in the syrup vehicle)

Interactions

Iron reduces the absorption of penicillamine, bisphosphonates, ciprofloxacin, entacapone, levodopa, levofloxacin, levothyroxine (give at least 2 hours apart), moxifloxacin, mycophenolate, norfloxacin, ofloxacin and zinc
Tetracycline — absorption of both iron and the antibiotic may be reduced when given together
Absorption of oral iron is reduced by calcium salts, magnesium salts (as magnesium trisilicate) and trientine
Chloramphenicol delays plasma iron clearance and incorporation of iron into red blood cells, and interferes with erythropoiesis
Some inhibition of iron absorption may occur with colestyramine, tea, eggs or milk; avoid concomitant use of iron with dimercaprol; oral iron antagonises the hypotensive effect of methyldopa

Clinical monograph

How it works

It provides elemental iron in the absorbable ferrous form, which is taken up in the duodenum and incorporated into haemoglobin to support erythropoiesis.

Prescribing in practice

Iron salts are a leading cause of accidental poisoning fatalities in young children, so keep all preparations well out of reach and counsel on safe storage.
Absorption is reduced by tea, antacids, calcium, and by chelation with tetracyclines, quinolones, levothyroxine and bisphosphonates, which should be separated in time.
Gastrointestinal upset, constipation and dark stools are common and may improve by taking the dose with or after food at the cost of slightly reduced absorption.

Monitoring

Check haemoglobin and iron indices after a few weeks to confirm an adequate response, continuing treatment for a period after normalisation to replenish stores.

Counselling the patient

Stools may turn black; this is harmless and expected.
Keep iron tablets away from children as overdose can be dangerous.
Avoid taking with tea, milk or indigestion remedies at the same time of day.

Evidence & guidelines

NICE guidance supports oral ferrous salts as first-line treatment for iron-deficiency anaemia, with parenteral iron reserved for intolerance or malabsorption.

Reference: NICE CKS; Stoffel et al 2019 (alternate-day dosing); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

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