Iron preparations. Antianaemic agents
ATC code: B03AA-IRON-ORAL (Oral iron (generic salt group))
Brand names – drugs
Feosol, Ferro-Sequels
Brand names – supplements
Solgar Gentle Iron, Thorne Iron Bisglycinate
Supplements are not tested in clinical trials and are not registered as medications.
Iron is a structural component of haem in haemoglobin and myoglobin and a cofactor for respiratory enzymes. Absorbed mainly in the duodenum and proximal jejunum. Absorption is regulated by hepcidin, an acute-phase protein that reduces absorption in inflammation. Ferrous iron (Fe²⁺, sulphate, fumarate, bisglycinate) is absorbed more readily than ferric iron (Fe³⁺, polymaltose) in patients without inflammation, but ferric forms cause less dyspepsia.
First line
Oral iron is first-line for mild-to-moderate iron deficiency anaemia. Starting daily dose is 60–100 mg elemental iron; alternate-day dosing is more effective than daily per RCTs (less hepcidin response, better bioavailability). Target haemoglobin rise is 10–20 g/L over 4 weeks. Total therapy duration is 3–6 months after haemoglobin normalises to replenish stores. Efficacy is supported by , , and the 2021 Lancet seminar.
In oral intolerance, severe anaemia (haemoglobin below 70 g/L), inflammatory bowel disease, or late pregnancy with anaemia, intravenous iron is used.
Sources
First line
Daily 30–60 mg elemental iron in all pregnant women from early pregnancy to delivery and for 6 weeks postpartum is -recommended for prevention of iron deficiency anaemia and obstetric complications. The 2015 Cochrane review (61 RCTs, more than 44,000 women) confirmed a 70% reduction in term anaemia and an 8% reduction in low birth weight. Russian clinical guidelines support routine use in pregnancy from early gestation.
Individual decision
In patients with ferritin below 30 µg/L and clinical symptoms (fatigue, reduced exercise tolerance, restless legs), iron therapy is justified. 2021 supports 4–6 weeks of oral therapy with follow-up ferritin. In women with heavy menstrual bleeding and low ferritin without anaemia, it is common practice. In symptomatic patients with ferritin above 30 µg/L, the decision is individualised given other likely fatigue causes.
Not recommended
In patients with normal ferritin, transferrin, and haemoglobin, iron therapy for chronic fatigue lacks evidence. Unnecessary iron administration without deficiency increases oxidative stress risk and can worsen concurrent inflammatory processes. “Iron for fatigue” without laboratory work-up is not recommended by any international guidelines.
Calcium reduces iron absorption by 40–60% at concurrent doses above 300 mg. Iron and calcium are separated by 2 hours. In long-term therapy with both, timing is planned to different parts of the day.
Ascorbic acid 100–200 mg increases ferrous iron absorption by 10–15% by reducing Fe³⁺ to Fe²⁺. The effect is stronger with concurrent than separated dosing. In guidance, vitamin C is optional with iron therapy – not considered mandatory.
Routine oral iron in pregnancy is encouraged by WHO. FDA category A at recommended doses. In severe anaemia with oral intolerance, intravenous iron is used after the first trimester.
Transfers into breast milk in minimal amounts. Breast milk iron content is independent of maternal intake at physiological doses. Infants over 6 months receive iron separately, regardless of maternal status.
iron (oral salts: sulfate, fumarate, gluconate, bisglycinate, polymaltose) is evaluated for the following indications with varying evidence strength: Iron supplementation in pregnancy (evidence tier A), Iron deficiency anemia (evidence tier A), Iron deficiency without anaemia (evidence tier B). See the full indication matrix with dosing and citations above on this page.
Common side effects of iron (oral salts: sulfate, fumarate, gluconate, bisglycinate, polymaltose) (≥ 1 in 100): Nausea, epigastric discomfort, Constipation or diarrhoea, Dark stools (normal, not indicative of bleeding), Metallic taste. See the Safety section for uncommon and serious reactions.
FDA category A. Routine oral iron in pregnancy is encouraged by WHO. FDA category A at recommended doses. In severe anaemia with oral intolerance, intravenous iron is used after the first trimester.
Transfers into breast milk in minimal amounts. Breast milk iron content is independent of maternal intake at physiological doses. Infants over 6 months receive iron separately, regardless of maternal status.
iron (oral salts: sulfate, fumarate, gluconate, bisglycinate, polymaltose) is contraindicated in: Haemochromatosis and other iron overload states; Haemolytic, aplastic, and sideroblastic anaemia; Iron absorption disorders (haemosiderosis, haemochromatosis); Repeated transfusions without ferritin monitoring; Hypersensitivity to components. Full list in the Safety section.
with normal ferritin, iron has no effect on fatigue. Unwarranted use increases oxidative stress. Check ferritin and complete blood count before buying an iron supplement.
safety differences with oral use are minor. Ferrous iron (Sorbifer, Feosol) is more effective at correcting deficiency; ferric forms (Maltofer) irritate the gastrointestinal tract less. The choice is a matter of tolerance.
non-haem iron from plant sources (buckwheat, pomegranate, apples) is absorbed less efficiently than haem iron from animal sources (red meat, liver, shellfish). In established anaemia, dietary correction is adjunctive – iron preparations are the main therapy.