For an 80‑year‑old male with iron‑deficiency anemia (hemoglobin 8.4 g/dL, ferritin 43 ng/mL) currently taking oral iron gluconate 300 mg daily, how many intravenous iron sucrose (Venofer) injections and what dose per injection are required to replace his iron deficit?

Iron Sucrose Dosing for 80-Year-Old Male with Iron Deficiency Anemia

For this 80-year-old male with hemoglobin 8.4 g/dL and ferritin 43 ng/mL, administer 5 injections of iron sucrose 200 mg each over a 14-day period (total 1000 mg). 1

Calculating the Total Iron Deficit

Using the Ganzoni Formula to determine total iron needed: 1

• Body weight (kg) × [target Hb - actual Hb (g/dL)] × 0.24 + 500 mg 1
• Assuming 70 kg body weight: 70 × (13 - 8.4) × 0.24 + 500 = 1,279 mg total iron needed

The simplified dosing approach for patients ≥50 kg with hemoglobin 7-10 g/dL recommends 1500-2000 mg total iron, which aligns with this calculation. 1

Number of Injections Required

For a total deficit of approximately 1500 mg, you need 7-8 rounds of 200 mg each. 1

However, the standard initial regimen is 5 doses of 200 mg given over 14 days (total 1000 mg), which is the FDA-approved dosing schedule for non-dialysis patients. 1 This should be administered first, followed by reassessment.

Dosing Schedule

• Dose per injection: 200 mg (maximum single dose) 1, 2
• Infusion time: 10 minutes per dose 2, 1
• Frequency: Every 2-3 days over 14 days to complete 5 doses 1
• Dilution: 200 mg in 100-150 mL normal saline 3, 4

Administration Protocol

• No test dose required for iron sucrose (unlike iron dextran) 2
• Resuscitation equipment must be immediately available during all infusions due to rare risk of anaphylaxis, though serious reactions occur in <1% of patients 2, 1
• Most reactions are complement activation-related pseudo-allergy (infusion reactions), not true anaphylaxis 2
• If mild flushing or paresthesias occur, stop the infusion and restart at a slower rate after 15 minutes 3

Monitoring and Follow-Up

Recheck hemoglobin, ferritin, and transferrin saturation at 4 weeks after completing the initial 5 doses. 1

Expected response: 1, 4

• Hemoglobin should increase by ≥2 g/dL within 4 weeks
• Mean hemoglobin increase is typically 3-4 g/dL
• 84-94% of patients respond adequately

If the target hemoglobin is not achieved after the initial 1000 mg:

• Administer 2-3 additional doses of 200 mg to reach the calculated total deficit of 1500 mg 1
• Investigate for ongoing blood loss or other causes of persistent anemia 1

Why IV Iron is Appropriate Here

This patient has failed oral iron therapy (ferritin remains low at 43 ng/mL despite oral iron gluconate 300 mg daily), which is a clear indication for IV iron. 5, 2 The 2024 AGA guidelines state that adherent patients on oral iron should show ferritin increase within a month; if not, IV iron should be used. 5

Critical Pitfalls to Avoid

• The most common error is stopping after 2-3 doses when patients need 5+ rounds to fully replete iron stores 1
• Do not give oral iron simultaneously with IV iron therapy 1
• Never exceed transferrin saturation >50% or ferritin >800 μg/L 1
• Do not administer during active bacterial infection 1
• Iron parameters should not be evaluated within 4 weeks of completing IV iron, as circulating iron interferes with assays 5