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Oral ferrous iron Pregnancy: UK SPC §4.6: There is no evidence of any harmful effects due to normal doses of ferrous gluconate in pregnant women and nursing mothers, but as with all drugs care should be exercised in administering this preparation during pregnancy and lactation. Iron is excreted in breast milk but not in significant amounts (about 0.5 mg/day).

Ferrous gluconate

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

Adult dose

Dose: Iron deficiency anaemia, using ferrous gluconate 300 mg coated tablets (each tablet contains 300 mg ferrous gluconate). Adults - prevention: two tablets daily. Treatment: four to six tablets daily in divided doses.
Route: Oral
Frequency: Prevention: daily. Treatment: daily, in divided doses. Best taken about one hour before meals.
VERBATIM UK SPC §4.2 (FERROUS GLUCONATE 300 MG COATED TABLETS, PL576300005, Medipoint UK Ltd): 'Adults: Prevention: Two tablets daily Treatment: Four to six tablets daily in divided doses Children 6-12 years: Prevention and treatment: One to three tablets daily in divided doses. Ferrous gluconate 300 mg coated tablets are best taken about one hour before meals.' §2: 'Ferrous gluconate 300.0 [mg/tablet]'. §4.1: 'The tablets are for oral administration in the prevention and treatment of iron deficiency anaemia.' The SPC prints no maximum daily dose and does not state the elemental iron content per tablet, so neither is given here. This SPC covers this one 300 mg coated tablet product; other ferrous gluconate preparations and strengths are not covered. Before starting treatment exclude underlying causes of anaemia, e.g. gastric erosions or colonic carcinoma (§4.4). The tablets contain sucrose (§4.4). The label carries the warning 'Contains iron. Keep out of the sight and reach of children, as overdose may be fatal'.

Paediatric dose

Dose: Children 6-12 years - prevention and treatment of iron deficiency anaemia: one to three 300 mg ferrous gluconate tablets daily in divided doses
Route: Oral
Frequency: Daily, in divided doses
THESE ARE THE LABEL'S OWN PAEDIATRIC FIGURES, NOT SCALED ADULT DOSES. VERBATIM §4.2: 'Children 6-12 years: Prevention and treatment: One to three tablets daily in divided doses.' Tablet = 300 mg ferrous gluconate (§2). The SPC gives no figure for children under 6 years or for adolescents over 12 years; none is implied, and none is given for neonates. Verify any under-18 dose against a children's formulary before use.

Dose adjustments

Renal

UK SPC §4.2 gives no renal impairment dose adjustment (no figure printed).

Hepatic

UK SPC §4.2 gives no hepatic dose figure. §4.3 lists alcoholism and hepatitis as contraindications to iron preparations.

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via MHRA Products — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to iron preparations or to any of the excipients
  • Haemochromatosis, haemosiderosis or haemoglobinuria
  • Patients receiving repeated blood transfusions or parenteral iron therapy
  • Anaemias not produced by iron deficiency (some conditions, such as thalassaemia, may cause excess storage of iron)
  • Alcoholism and hepatitis
  • Active peptic ulcer, regional enteritis and ulcerative colitis

Side effects

  • Large doses may cause gastro-intestinal discomfort, anorexia, diarrhoea, nausea, heartburn and vomiting; reported in up to 20% or more of patients and related to the amount of elemental iron taken rather than the type of preparation
  • Continued administration may result in constipation and faecal impaction; darkening of stools may occur
  • Higher doses may have irritant and corrosive effects on the gastro-intestinal mucosa; necrosis and perforation may occur, and stricture formation may follow
  • Symptoms of overdose, which may not appear for several hours: epigastric pain, diarrhoea, vomiting and haematemesis; circulatory failure may follow if diarrhoea and haemorrhage are severe
  • Rarely, allergic reactions

Interactions

  • Antacids containing calcium salts, carbonates or magnesium trisilicate, and other medicines containing bicarbonates, carbonates, oxalates or phosphates: decrease iron absorption; do not give iron within 1 hour before or 2 hours after them
  • Tetracyclines: reduced absorption of both; give the iron salt 3 hours before or 2 hours after the tetracycline
  • Levothyroxine: iron reduces its absorption; leave 2 hours between levothyroxine and iron
  • Penicillamine: iron reduces absorption and may decrease penicillamine's effect; leave 2 hours between them
  • Bisphosphonates (give at least two hours apart), fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin, norfloxacin, ofloxacin), entacapone, mycophenolate: oral iron reduces their absorption
  • Eltrombopag: iron possibly reduces absorption - leave 4 hours; also possibly nalidixic acid, levodopa and carbidopa
  • Acetohydroxamic acid: chelation reduces absorption of both drugs
  • Dimercaprol: avoid concomitant use (formation of toxic compounds)
  • Coffee, eggs, milk and milk products, tea and whole grain breads and cereals slow iron absorption; trientine and zinc salts reduce it; colestyramine may inhibit it; proton pump inhibitors may reduce it
  • Vitamin E: may impair the haematologic response in iron deficiency anaemia; large doses of iron may increase vitamin E requirements
  • Oral iron antagonises the hypotensive effect of methyldopa; oral chloramphenicol delays plasma iron clearance and interferes with erythropoiesis; neomycin may alter iron absorption

Monitoring

  • Exclude underlying causes of anaemia (e.g. gastric erosions or colonic carcinoma) before starting treatment
  • Use with caution in haemolytic anaemia, iron-absorption diseases, existing gastro-intestinal disease, intestinal strictures and diverticulae
  • Caution in the elderly, who may be at risk of serious adverse reactions
  • Patients with rare hereditary problems of fructose intolerance, glucose-galactose malabsorption or sucrose-isomaltase insufficiency should not take it (contains sucrose)

Clinical monograph

How it works

It supplies elemental iron in the absorbable ferrous form for duodenal uptake and incorporation into haemoglobin, supporting red cell production.

Prescribing in practice

  • Iron salts are a major cause of accidental poisoning deaths in children, so emphasise secure storage out of their reach.
  • Separate from tea, antacids, calcium and chelating drugs such as tetracyclines, quinolones, levothyroxine and bisphosphonates to preserve absorption of both agents.
  • It contains less elemental iron per tablet than some other salts, so the regimen and tablet count differ even though gastrointestinal effects are similar.

Monitoring

Recheck haemoglobin and iron indices after several weeks to confirm response, continuing therapy to rebuild iron stores once levels normalise.

Counselling the patient

  • Black stools are expected and not a cause for concern.
  • Store safely away from children because overdose can be serious.
  • Take separately from tea, milk and indigestion remedies.

Evidence & guidelines

NICE recommends oral ferrous salts as first-line therapy for iron-deficiency anaemia, reserving intravenous iron for intolerance or malabsorption.

Reference: 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).

Related

Curated clinical cross-links plus same-class fallbacks.

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