Oral ferrous iron Pregnancy: Use of any drug during the first trimester of pregnancy should be avoided if possible, so administration of iron during the first trimester requires definite evidence of iron deficiency. Prophylaxis of iron deficiency during the remainder of pregnancy is justified.

Ferrous sulfate

Brand names: Ferrograd

Used in: Anaemia

Ferrous sulfate is an oral ferrous (iron[II]) salt and the standard first-line treatment for 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: Iron-deficiency anaemia, therapeutic: one 200 mg ferrous sulfate coated tablet two to three times daily. Prophylaxis: one 200 mg tablet daily.

Route: Oral — tablets should not be sucked, chewed or kept in the mouth, but swallowed whole with water. Take before meals or during meals, depending on gastrointestinal tolerance.

Frequency: Two to three times daily (therapeutic); once daily (prophylaxis)

SOURCE PRODUCT: Ferrous Sulfate 200 mg Coated Tablets (UK SPC). ELDERLY: as for adults. PAEDIATRIC: the SPC states 'Children: this presentation is not recommended' — no paediatric dose is given, so paedDose is null. Verify any paediatric use against a children's formulary and an age-appropriate formulation. DURATION: treatment should generally not exceed 3 months after correction of the anaemia. Co-existing vitamin B12 or folic acid deficiency should be ruled out, since combined deficiency produces a microcytic blood film. ABSORPTION: patients post-gastrectomy have poor absorption of iron. CAUTIONS: history of peptic ulcer, and inflammatory bowel disease including regional enteritis and ulcerative colitis; care in patients with intestinal strictures or diverticulae. Because of the risk of mouth ulceration and tooth discolouration, do not suck, chew or keep tablets in the mouth. Patients with iron overload are particularly susceptible to infection — treat iron overload with caution. Long-term treatment carries a definite risk of dental caries; the tablets contain sugar (care in diabetes) and should be avoided in rare hereditary fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency. Contains less than 1 mmol (23 mg) sodium per tablet. Label warning: contains iron — keep out of the sight and reach of children, as overdose may be fatal. FALLBACK SOURCE NOT USED: the openFDA record in this bundle is a Boiron homeopathic 'Ferrum sulphuricum' pellet product (dissolve 5 pellets under the tongue 3 times a day), which is a different product and indication and was deliberately not used.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Haemosiderosis and haemochromatosis
Active peptic ulcer
Repeated blood transfusion
Haemolytic anaemia
Oral and parenteral iron preparations should not be used concomitantly

Side effects

Abdominal pain, nausea and vomiting (usually dose related)
Constipation and diarrhoea
Dark stools
Contact irritation resulting in erosion or ulceration, particularly if tablets become lodged in the upper gastrointestinal tract; mouth ulceration reported post-marketing where tablets are chewed, sucked or kept in the mouth (elderly patients and those with deglutition disorders may also be at risk of oesophageal lesions, or bronchial necrosis if the wrong route is taken)
Allergic reactions

Interactions

Compounds containing calcium, magnesium (including antacids and mineral supplements), bicarbonates, carbonates, oxalates or phosphates may impair iron absorption — separate administration by at least 2 hours
Tetracyclines — iron and tetracyclines reduce each other's absorption; separate administration by 2 to 3 hours. Quinolones — iron may reduce absorption; separate by at least 2 hours. Chloramphenicol delays plasma clearance of iron and its incorporation into red blood cells by interfering with erythropoiesis
Bisphosphonates — absorption is reduced when taken concurrently with iron; separate administration by at least 2 hours
Colestyramine impairs iron absorption; concomitant administration of oral iron and dimercaprol should be avoided
Dopaminergics (co-careldopa, entacapone, levodopa) — oral iron may reduce absorption. Oral iron may antagonise the antihypertensive effect of methyldopa. Absorption of iron is impaired by tea, eggs or milk

Clinical monograph

How it works

It delivers elemental iron in the ferrous form, absorbed in the duodenum and used for haemoglobin synthesis and replenishment of body iron stores.

Prescribing in practice

Iron preparations are a frequent cause of accidental poisoning fatalities in children, so safe storage out of reach is essential.
Absorption is impaired by tea, antacids, calcium and proton pump inhibitors, and it chelates tetracyclines, quinolones, levothyroxine and bisphosphonates, so dosing should be separated.
Constipation, nausea and abdominal discomfort are common and may be eased by taking with food, with alternate-day dosing an option to improve tolerability.

Monitoring

Check haemoglobin after a few weeks to confirm a response and continue treatment after normalisation to restore iron stores.

Counselling the patient

Expect black stools, which are harmless.
Keep tablets safely away from children due to overdose risk.
Do not take at the same time as tea, milk or antacids.

Evidence & guidelines

NICE identifies oral ferrous sulfate as the first-line treatment for iron-deficiency anaemia in adults.

Reference: NICE CKS iron-deficiency anaemia; 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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