Can you give oral (PO) iron?

Oral Iron Supplementation for Iron Deficiency

Yes, oral iron is an effective first-line treatment for iron deficiency and should be given as 200 mg of elemental iron per day in 2-3 divided doses for adults. 1

Recommended Oral Iron Formulations

• Ferrous sulfate (325 mg tablet containing 65 mg elemental iron) is preferred as the least expensive iron formulation with good bioavailability 1
• Alternative formulations include ferrous fumarate (325 mg tablet containing 108 mg elemental iron) and ferrous gluconate (325 mg tablet containing 35 mg elemental iron) 1
• Iron polysaccharide complex is more expensive and has not shown superior efficacy or tolerability compared to traditional iron salts 1

Dosing Recommendations

• Standard adult dosing: 200 mg of elemental iron daily, divided into 2-3 doses 1
• For pediatric patients: 2-3 mg/kg/day of elemental iron 1
• Alternative dosing: Once-daily or every-other-day dosing may improve tolerance while maintaining efficacy 1, 2
• Morning administration may be more effective due to circadian variations in hepcidin levels 2

Administration Guidelines

• Oral iron is best absorbed when taken without food or other medications 1
• Taking iron with food reduces absorption by up to 50% 1
• Adding vitamin C (ascorbic acid 250-500 mg) with iron may enhance absorption 1
• Avoid taking iron within 2 hours of tetracycline antibiotics as iron interferes with tetracycline absorption 3, 4
• Avoid taking with aluminum-based phosphate binders which can reduce iron absorption 1

Common Side Effects and Management

• Gastrointestinal side effects are common: nausea, constipation, diarrhea, abdominal discomfort 1
• GI side effects are significantly more common with oral ferrous sulfate than placebo (OR 2.32) 1
• For patients with poor tolerance:
  • Start with lower doses and increase gradually 1
  • Try smaller, more frequent doses 1
  • Consider switching to a different iron formulation 1
  • Try taking at bedtime if daytime symptoms are problematic 1

Duration of Treatment

• Continue oral iron for 3 months after iron deficiency has been corrected to replenish stores 1
• Monitor hemoglobin and red cell indices at 3-month intervals for the first year, then after another year, and if symptoms of anemia develop 1

When to Consider IV Iron Instead of Oral Iron

• Patient intolerance to oral iron despite dose adjustments 1
• Ferritin levels do not improve with a trial of oral iron 1
• Conditions with impaired iron absorption (inflammatory bowel disease with active inflammation, post-bariatric surgery) 1
• Chronic kidney disease patients on hemodialysis 1
• Ongoing blood loss or severe anemia (Hb < 10 g/dL) 1

Monitoring Response

• Check hemoglobin and red cell indices after 4 weeks of therapy 1
• If inadequate response, consider adding vitamin C, checking compliance, or switching to IV iron 1
• Once normal, monitor hemoglobin and red cell indices every 3 months for 1 year, then after another year 1

Oral iron supplementation remains a safe, effective, and economical first-line treatment for iron deficiency in most patients when administered appropriately with attention to optimizing absorption and managing side effects.