What is the recommended iron supplement formula for treating iron deficiency?

Recommended Iron Supplement Formulations for Treating Iron Deficiency

For most patients with iron deficiency, oral ferrous sulfate at a dose of 200 mg twice daily is the recommended first-line iron supplement formula due to its effectiveness, availability, and low cost. 1

Oral Iron Supplementation Options

First-Line Oral Iron Therapy

• Ferrous sulfate 200 mg twice daily (contains approximately 65 mg elemental iron per tablet) is the most commonly recommended and cost-effective oral iron supplement 1
• Lower doses may be as effective and better tolerated in patients experiencing side effects 1
• Treatment should continue for 3 months after iron deficiency has been corrected to ensure replenishment of iron stores 1

Alternative Oral Iron Formulations

• Ferrous gluconate (27-38 mg elemental iron per tablet) 1
• Ferrous fumarate (106-150 mg elemental iron per tablet) 1
• Polysaccharide-iron complex (variable elemental iron content) 1
• Ferrous bisglycinate (25 mg elemental iron per tablet) - may be better tolerated by some patients but no evidence of superior efficacy 1

Optimizing Oral Iron Administration

• Once-daily dosing is sufficient; more frequent dosing increases side effects without improving absorption 1
• Alternate-day dosing may improve tolerance and absorption compared to daily dosing 1, 2
• Morning administration is preferable due to circadian variations in hepcidin levels 2
• Taking iron with 80 mg vitamin C (ascorbic acid) on an empty stomach may improve absorption 1
• Avoid consuming tea or coffee within one hour after taking iron supplements as they inhibit absorption 1

Intravenous Iron Supplementation

Indications for IV Iron

• Intolerance to oral iron preparations 1
• Failure to respond to oral iron (no increase in hemoglobin of 1 g/dL within 2 weeks in anemic patients) 1
• Conditions with impaired absorption (celiac disease, post-bariatric surgery) 1, 3
• Active inflammatory bowel disease 1, 3
• When iron loss exceeds oral iron absorption capacity 1
• Critically ill patients with iron deficiency confirmed by low hepcidin levels 1

IV Iron Formulations

• Ferric carboxymaltose: Can be given as 750-1000 mg in a single dose over 15 minutes 1, 4
• Iron sucrose: Typically administered as 200 mg per dose 1
• Ferric derisomaltose: Can be given as 1000 mg in a single dose 1
• Ferumoxytol: Administered as 510 mg per dose 1
• Iron dextran (low molecular weight): Can be given as doses >1000 mg but requires test dose due to anaphylaxis risk 1

Special Considerations

Dosing for Specific Populations

• For enteral nutrition: Provide 18-30 mg iron per day with 1500 kcal 1
• For parenteral nutrition: Provide at least 1 mg/day of elemental iron 1
• For female athletes: Consider 100 mg/day iron in divided doses for 8-12 weeks with vitamin C supplementation 1
• For pregnant women: Low-dose supplementation (30 mg/day) may be as effective as higher doses while reducing side effects 1

Monitoring Response

• Hemoglobin should increase by 1 g/dL within 2 weeks of supplementation in anemic patients 1
• Ferritin should increase within one month in adherent patients on oral iron 1
• After normalization, monitor hemoglobin and red cell indices at 3-month intervals for 1 year, then after another year 1

Common Pitfalls and Caveats

• Side effects of oral iron include constipation (12%), diarrhea (8%), and nausea (11%) 1
• Enteric-coated formulations may improve tolerability but decrease absorption 1
• Excessive iron supplementation should be avoided to prevent iron overload, especially in high-risk patients 5
• Iron supplementation during infections and hemato-oncologic disease should be balanced against potential adverse effects on disease course 1
• In patients with iron overload conditions or hemochromatosis, iron stores should be reduced by repeated venesection rather than supplemented 1