What are the indications, dosing schedule, monitoring parameters, adverse effects, contraindications, and alternative intravenous iron options for iron sucrose in treating iron‑deficiency anemia?

Iron Sucrose for Iron-Deficiency Anemia

Iron sucrose is a safe and effective intravenous iron formulation that requires multiple infusions (typically 5–10 doses of 200 mg each) to deliver a total dose of 1000–2000 mg, making it less convenient than newer single-dose alternatives like ferric carboxymaltose, but it remains an excellent option particularly for hemodialysis patients and those requiring smaller, incremental dosing. 1

Indications

Iron sucrose is indicated for iron-deficiency anemia in the following clinical scenarios:

• Intolerance or failure of oral iron therapy after an adequate trial (typically 4 weeks without ferritin rise) 2, 3
• Active inflammatory bowel disease where hepcidin activation impairs oral iron absorption 1, 4
• Chronic kidney disease patients on hemodialysis, where it can be administered directly into the dialysis line 5
• Severe anemia (hemoglobin <10 g/dL) requiring more rapid correction than oral iron can provide 6
• Gastrointestinal blood loss with documented iron deficiency 7
• Pregnancy-related iron-deficiency anemia when oral iron fails or is not tolerated 8

Dosing Schedule

Standard Non-Dialysis Regimen

• 200 mg per dose administered as an undiluted IV push over 10 minutes 5
• No test dose required (unlike iron dextran formulations) 5, 9
• Total dose typically 1000–2000 mg depending on hemoglobin level and body weight 2
• Frequency: 5 doses over 14 days for a 1000 mg total, or 7–10 doses for higher requirements 2

Hemodialysis-Specific Regimen

• 100 mg undiluted IV push over 5 minutes for ten consecutive dialysis sessions (total 1000 mg) 5, 9
• Can be administered 2–3 times weekly directly into the hemodialysis line 5

High-Dose Single Infusion (Alternative)

• 7 mg/kg body weight (maximum 500 mg) diluted and infused over 3.5 hours 5, 7
• This regimen is used in select populations (e.g., IBD, gastrointestinal bleeding) but is less common 4, 7

Calculating Total Iron Requirement

Simplified weight- and hemoglobin-based approach (preferred over Ganzoni formula): 2

Body Weight	Hemoglobin Level	Total Iron Dose	Number of 200 mg Doses
≥50 kg	10–12 g/dL (women) or 10–13 g/dL (men)	1000–1500 mg	5–7 doses
≥50 kg	7–10 g/dL	1500–2000 mg	7–10 doses
≥50 kg	<7 g/dL	Add 500 mg to above	Add 2–3 doses

Monitoring Parameters

Baseline Assessment

• Complete blood count (hemoglobin, MCV) 5
• Serum ferritin (typically <30 ng/mL in iron deficiency) 2
• Transferrin saturation (typically <20% in iron deficiency) 5

During Treatment

• Blood pressure monitoring during and immediately after each infusion 9
• Observation for adverse effects for at least 30 minutes post-infusion 6
• Resuscitation equipment must be immediately available 2

Post-Treatment Follow-Up

• Recheck hemoglobin, ferritin, and transferrin saturation at 4 weeks after the final dose 2, 5
• Do NOT recheck iron parameters within 4 weeks of the last infusion, as circulating iron falsely elevates ferritin 2, 5
• Expected response: Hemoglobin increase ≥2 g/dL within 4 weeks 2, 3
• Long-term monitoring: Check blood count every 3 months for 12 months, then every 6 months for 2–3 years 1

Target Parameters After Repletion

• Transferrin saturation ≥20% (but <50% to avoid overload) 5
• Serum ferritin ≥100 ng/mL (but preferably ≤500 ng/mL, maximum 800 ng/mL) 5
• Hemoglobin 11–12 g/dL for hemodialysis patients 5

Adverse Effects

Common (Mild)

• Arthralgia, hypotension, injection site reactions 5
• Gastrointestinal symptoms (much less common than with oral iron; only 4.5% discontinuation rate vs. 20.8% with oral iron sulfate) 4

Rare but Serious

• Anaphylactic reactions: Extremely rare (<1:200,000 administrations) 5
• Hypersensitivity reactions: Approximate incidence 0.5%, but serious adverse reaction rates are low and similar to oral iron 1
• Hypophosphatemia: Occurs in only 1% of iron sucrose patients (compared to 58% with ferric carboxymaltose) 1, 6

Safety Profile

• No serious adverse drug reactions were recorded in the North American clinical trial of 77 patients, including those with previous iron dextran sensitivity, other drug allergies, or concurrent ACE inhibitor use 9
• Generally well tolerated with a clinically manageable safety profile when using appropriate dosing and monitoring 3

Contraindications

Absolute Contraindications

• Active bacteremia or ongoing infection (withhold until infection is controlled) 1, 5
• Hypersensitivity to iron sucrose or any of its excipients 6
• Anemia not attributed to iron deficiency 6
• Evidence of iron overload (ferritin >800 ng/mL or transferrin saturation >50%) 5

Relative Contraindications (Use with Caution)

• Acute or chronic infection (assess risk/benefit; infection is not an absolute contraindication if treatment of anemia is critical) 1, 5
• Known drug allergies, especially severe asthma, eczema, or atopic allergies 6

Alternative Intravenous Iron Options

Ferric Carboxymaltose (Preferred for Convenience)

• Maximum single dose: 1000 mg (vs. 200 mg for iron sucrose) 1, 6
• Infusion time: 15–30 minutes for full dose 6
• Total dose delivery: 1–2 infusions vs. 5–10 for iron sucrose 1, 6
• Major advantage: Fewer clinic visits and faster iron repletion 6
• Major disadvantage: 58% incidence of hypophosphatemia (vs. 1% with iron sucrose); avoid in patients requiring repeat infusions within 3 months 1, 6
• Cost: Higher acquisition cost (£217.50 per gram) vs. iron sucrose (£70.80 per gram), but potential overall savings due to fewer visits 6

Iron Derisomaltose (Iron Isomaltoside 1000)

• Maximum single dose: 1000 mg 1
• Infusion time: 15–40 minutes 1
• Hypophosphatemia rate: 4% (intermediate between iron sucrose and ferric carboxymaltose) 1

Low Molecular Weight Iron Dextran

• Can deliver total dose in one infusion but requires 4–6 hours infusion time 1
• Rarely used due to inconvenience and higher risk of hypersensitivity compared to newer formulations 1

Clinical Pearls and Common Pitfalls

Most Common Error

Stopping after 2–3 doses when patients need 5–10 rounds to fully replete iron stores. Always calculate total iron deficit before starting treatment and complete the full course. 2

Timing of Laboratory Reassessment

Do not recheck iron parameters within 4 weeks of the last infusion; circulating iron interferes with assays, leading to falsely elevated ferritin. 2, 5

When to Suspect Treatment Failure

If hemoglobin does not increase by ≥2 g/dL within 4 weeks after completing the full course, investigate for:

• Ongoing blood loss 2
• Chronic inflammation or malignancy 1
• Vitamin B12 or folate deficiency 2
• Hemoglobinopathy or other causes of anemia 2

Infection Considerations

Caution is advised regarding parenteral iron in acute/chronic infection, but studies show no significant increase in clinically important infective episodes. Infection should not be regarded as an absolute contraindication if the risk/benefit assessment favors treatment, though it should be withheld in ongoing bacteremia. 1

Concurrent Oral Iron

Do not give oral iron simultaneously with IV iron therapy; it does not enhance efficacy and may increase side effects. 2

Iron Sucrose vs. Ferric Carboxymaltose: Clinical Decision Algorithm

Choose iron sucrose when:

• Patient requires repeat infusions within 3 months (to avoid hypophosphatemia) 1, 6
• Patient is on hemodialysis (ease of administration through dialysis line) 5
• Cost is a primary concern and multiple visits are feasible 6

Choose ferric carboxymaltose when:

• Patient needs rapid iron repletion with minimal clinic visits 6
• Patient has heart failure with iron deficiency (proven cardiovascular benefit) 6
• Patient has severe anemia (Hb <10 g/dL) requiring urgent correction 6
• Patient is unlikely to complete a multi-dose regimen due to compliance concerns 6