What is the dosing regimen for ferric gluconate (iron replacement therapy) in severe iron deficiency anemia?

Ferric Gluconate Dosing for Severe Iron Deficiency Anemia

For severe iron deficiency anemia, ferric gluconate should be administered intravenously at a maximum individual dose of 125 mg per infusion, given as a slow IV infusion over 30-60 minutes, with no test dose required. 1

Standard Dosing Regimens

For Hemodialysis Patients

• Administer 125 mg IV weekly for 8 consecutive weeks (total cumulative dose: 1,000 mg) 1
• Infuse in 50-100 mL normal saline over 30-60 minutes 1
• This regimen is more practical than smaller, more frequent doses for non-dialysis patients 1

For Non-Hemodialysis Patients (CKD, Peritoneal Dialysis)

• The manufacturer recommends not exceeding 125 mg per infusion 1
• However, research evidence supports that 250 mg doses infused over 1-4 hours are safe and well-tolerated in patients who have previously tolerated 125 mg doses 2, 3
• Higher doses (250 mg) allow more rapid iron repletion and are more convenient for patients not on maintenance hemodialysis 2, 3

Pediatric Dosing

• Weight-based dosing: 1.0 mg/kg weekly, not to exceed 125 mg per dose 4
• For children <20 kg requiring loading doses:
  • 10 kg: 25 mg per dose for 10-dose course 1
  • 10-20 kg: 50 mg per dose for 10-dose course 1
  • ≥20 kg: 100 mg per dose for 10-dose course 1

Administration Guidelines

Infusion Rate and Safety

• Standard rate: 125 mg in 50-100 mL saline over 30-60 minutes (approximately 2.1-4.2 mg/min) 1
• Faster infusions (over 10 minutes at 12.5 mg/min) are FDA-approved but may increase risk of transferrin oversaturation artifacts 1
• No test dose is required, unlike iron dextran 1

Critical Safety Considerations

• Ferric gluconate does not carry the anaphylaxis boxed warning that iron dextran does 1
• Adverse events are uncommon (approximately 5% with higher doses) and include transient nausea, pruritus, hypotension, or diarrhea 3, 5
• Emergency medications (epinephrine, diphenhydramine, corticosteroids) should be immediately available, though severe reactions are rare 1

Monitoring Parameters

Timing of Iron Studies

• Do not measure transferrin saturation (TSAT) or ferritin within 2-7 days after the last dose for doses of 100-125 mg 1
• For single doses ≥1,000 mg, wait at least 14 days before measuring iron indices 1
• This avoids spuriously elevated levels from circulating drug iron 1

Target Iron Parameters

• Measure TSAT and ferritin after completing the loading course 1
• During maintenance therapy, monitor iron status every 3 months 1
• Target TSAT >20% and ferritin 100-500 ng/mL for optimal erythropoiesis 1

Comparison to Other IV Iron Formulations

Ferric gluconate is less practical than newer formulations for severe anemia because:

• Maximum single dose is only 125 mg (vs. 750-1,000 mg for ferric carboxymaltose or ferric derisomaltose) 1
• Requires 8 separate infusion visits to deliver 1,000 mg total 1
• Newer formulations that deliver 1,000 mg in 1-2 infusions are preferred when rapid iron repletion is needed 1

Cost Considerations

• Ferric gluconate is significantly less expensive: approximately $610 for 1,000 mg total dose (8 infusions of 125 mg) 1
• Compare to ferric carboxymaltose at $3,470 or ferric derisomaltose at $3,896 for equivalent dosing 1
• However, this does not include the cost of 8 separate infusion visits 1

When to Use Ferric Gluconate

Ferric gluconate remains appropriate for:

• Hemodialysis patients receiving regular dialysis treatments where weekly dosing is convenient 1
• Patients with cost constraints where the lower medication cost outweighs multiple infusion visits 1
• Patients who have had reactions to iron dextran, as ferric gluconate has a superior safety profile 1, 2

Consider alternative IV iron formulations when:

• Rapid iron repletion is needed (severe anemia with hemoglobin <8 g/dL) 1
• Patient cannot return for multiple infusion visits 1
• Total iron deficit exceeds 1,000 mg 1

Common Pitfalls to Avoid

• Do not exceed 125 mg per dose per manufacturer guidelines, though research supports 250 mg doses are safe in selected patients 1, 2
• Do not measure iron studies too soon after infusion, as this creates spuriously elevated values 1
• Do not use oral iron concurrently with IV iron therapy, as it is unnecessary and increases side effects without benefit 1
• Do not confuse ferric gluconate with iron dextran—they have different dosing limits and safety profiles 1