What is the recommended intravenous dosing regimen of ferric gluconate for an adult with iron‑deficiency anemia?

Ferric Gluconate IV Dosing for Iron Deficiency Anemia

For adults with iron deficiency anemia, administer ferric gluconate 125 mg IV infused over 60 minutes, once weekly for 8 consecutive weeks (total cumulative dose of 1,000 mg), without requiring a test dose. 1, 2

Standard Dosing Protocol

Adult Dosing

• 125 mg IV weekly for 8 weeks is the established regimen for hemodialysis patients with iron deficiency anemia 1, 2
• Each 125 mg dose should be diluted in 50-100 mL normal saline and infused over 30-60 minutes (infusion rate approximately 2.1-4.2 mg/min) 2
• The manufacturer recommends not exceeding 125 mg per individual infusion 1, 2
• Total cumulative dose reaches 1,000 mg after completing the 8-week course 2

Test Dose Requirements

• No test dose is required for ferric gluconate, unlike iron dextran which mandates a 25 mg test dose 1, 2
• This represents a significant safety advantage over iron dextran formulations 1

Higher Dose Considerations

While the FDA-approved maximum is 125 mg per dose, research demonstrates that 250 mg doses infused over 1 hour are safe and well-tolerated in hemodialysis patients who previously tolerated 125 mg doses 3, 4. However, this higher dosing:

• Is not manufacturer-recommended and should be reserved for selected patients 2
• Showed only 5% incidence of side effects (diarrhea, vomiting, low back pain, hypotension) in one study 3
• Was well-tolerated in 590 administrations to 144 hemodialysis patients, with only one patient developing intolerance 4

Doses of 500 mg have been associated with transient nausea, pruritus, and hypertension, making them less advisable 5

Monitoring Parameters

Timing of Iron Studies

• Do not measure transferrin saturation or ferritin within 2-7 days after the last dose for 100-125 mg doses, as this creates spuriously elevated values 2
• Repeat iron studies 3-4 weeks after completing the treatment course 2

Target Values

• Maintain transferrin saturation >20% and ferritin 100-500 ng/mL for optimal erythropoiesis 1, 2
• Withhold iron therapy if transferrin saturation exceeds 50% or ferritin exceeds 800 ng/mL to avoid iron overload 1
• Monitor these parameters at least every 3 months during maintenance therapy 1

Clinical Context and Alternatives

When Ferric Gluconate is Appropriate

• Hemodialysis patients requiring maintenance iron therapy 1, 2
• Patients with cost constraints (approximately $610 for 1,000 mg total dose versus $3,470-$3,896 for newer formulations) 2
• Patients who have had reactions to iron dextran 2, 6

When to Consider Alternatives

Ferric gluconate is less practical than newer IV iron formulations for severe anemia requiring rapid repletion 1, 2. Consider ferric carboxymaltose (750 mg per dose) or ferric derisomaltose (1,000 mg per dose) when:

• Rapid iron repletion is needed 2
• Patient cannot return for multiple infusion visits 2
• Total iron deficit exceeds 1,000 mg 2

These newer agents deliver 1,000 mg in 1-2 infusions compared to 8 weekly visits for ferric gluconate 1, 2

Pediatric Dosing

For children on hemodialysis:

• 1.0 mg/kg IV weekly, not to exceed 125 mg per dose 2, 7
• Specific weight-based adjustments for children under 20 kg 2
• Ferric gluconate has not been established as safe and effective in pediatric patients per FDA labeling 1

Critical Safety Considerations

Contraindications

• Active infection or bacteremia is an absolute contraindication to IV iron therapy 8
• History of anaphylaxis to ferric gluconate 8

Common Adverse Effects

• Hypotension, hypertension, nausea, vomiting, diarrhea, pain, fever, dyspnea, pruritus, headaches, and dizziness occur in 1-2% of patients 8
• Anaphylaxis-like reactions occur in fewer than 1% of administrations 1
• Fatalities have not been reported with ferric gluconate, unlike iron dextran 1

Emergency Preparedness

• Administer in a setting with personnel trained to provide emergency treatment 1
• Have immediate access to epinephrine, diphenhydramine, and corticosteroids 1

Common Pitfalls to Avoid

• Do not use oral iron concurrently with IV iron therapy—it is unnecessary and increases side effects without benefit 2
• Do not confuse ferric gluconate with iron dextran—they have different dosing limits and safety profiles 2
• Do not check iron parameters too soon after infusion (wait at least 2-7 days) 2
• Do not exceed 125 mg per dose per manufacturer guidelines, though research supports higher doses in selected patients 2, 4