What is the recommended dosage and administration of ferrous sulfate (iron supplement) in liquid form for treating iron deficiency anemia?

Ferrous Sulfate Liquid Form: Dosing and Administration

For treating iron deficiency anemia with ferrous sulfate liquid, administer once daily at a dose providing 50-100 mg of elemental iron, which translates to approximately 10-20 mL of standard ferrous sulfate drops (125 mg/mL formulation providing 25 mg/mL elemental iron). 1

Recommended Dosing Strategy

Standard Dosing

• Once-daily dosing is preferred over multiple daily doses, as studies show that 60 mg elemental iron taken once daily stimulates hepcidin levels, reducing subsequent iron absorption by 35-45%, making the overall absorption similar to divided doses 1
• Target 50-100 mg elemental iron daily for adults with iron deficiency anemia 1
• For ferrous sulfate liquid (drops at 125 mg/mL concentration = 25 mg/mL elemental iron), this requires approximately 2-4 mL per dose 1

Alternative Dosing for Intolerance

• Every-other-day dosing may improve tolerability with similar or superior fractional iron absorption compared to daily dosing 1
• If standard once-daily dosing causes gastrointestinal side effects, reduce to every-other-day administration rather than switching formulations 1

Available Liquid Formulations

The British Society of Gastroenterology guidelines identify these liquid iron preparations 1:

• Ferrous sulfate drops: 125 mg/mL (25 mg/mL elemental iron) 1
• Ferrous fumarate liquid: 140 mg/5 mL (45 mg/5 mL elemental iron) 1
• Sodium feredate liquid: 190 mg/5 mL (27.5 mg/5 mL elemental iron) 1

Ferrous sulfate remains the gold standard due to established efficacy, acceptable tolerability, and lowest cost, despite being more expensive in liquid form than tablets 1, 2, 3

Administration Guidelines

Timing and Absorption Enhancement

• Add vitamin C (ascorbic acid) to enhance iron absorption 1
• Avoid tea and coffee within one hour of iron administration, as these are powerful inhibitors of iron absorption 1
• Liquid preparations may be better tolerated when tablets are not 1

Treatment Duration

• Continue therapy for approximately 3 months after hemoglobin normalization to ensure adequate repletion of marrow iron stores 1
• Monitor hemoglobin response within the first 4 weeks; expect a rise of approximately 2 g/dL after 3-4 weeks 1

When to Switch to Intravenous Iron

Consider parenteral iron when 1:

• Oral iron is not tolerated despite dose reduction or alternate-day dosing
• Hemoglobin fails to increase by 1 g/dL within 2 weeks of supplementation 1
• Ferritin levels do not improve after one month of adherent oral therapy 1
• Conditions causing impaired absorption exist (bariatric surgery, active inflammatory bowel disease) 1

Common Pitfalls to Avoid

• Do not prescribe multiple daily doses: This increases hepcidin levels and paradoxically reduces overall iron absorption while increasing gastrointestinal side effects 1
• Do not delay treatment: Iron replacement therapy should not be deferred while awaiting diagnostic investigations unless colonoscopy is imminent 1
• Do not assume treatment failure prematurely: Poor response is usually due to non-compliance, continued blood loss, or malabsorption rather than formulation inadequacy 1

Monitoring Parameters

• Check hemoglobin at 4 weeks to confirm response 1
• After normalization, monitor blood counts every 3 months for one year, then annually 1
• Continue treatment for 3 months post-normalization to replenish iron stores 1