What are the indications, dosing regimen, expected therapeutic effects, and adverse reactions of intravenous iron sucrose?

Iron Sucrose: Indications, Dosing, Therapeutic Effects, and Adverse Reactions

Iron sucrose is a safe and effective intravenous iron formulation that requires no test dose, can be administered as 200 mg over 10 minutes, and is particularly well-suited for hemodialysis patients, inflammatory bowel disease, and patients requiring multiple smaller doses with minimal hypophosphatemia risk. 1

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Indications for Iron Sucrose

Iron sucrose is recommended for patients with iron deficiency anemia who have failed or cannot tolerate oral iron therapy, particularly those with active inflammatory bowel disease where hepcidin-mediated inhibition reduces oral iron absorption. 1

Specific Clinical Scenarios:

• Hemodialysis patients requiring ongoing iron supplementation through the dialysis circuit 1
• Active inflammatory bowel disease with hemoglobin impairment from chronic inflammation 1
• Pregnancy-related iron deficiency anemia when oral iron fails or causes intolerable gastrointestinal side effects 2
• Chronic kidney disease patients both before and after dialysis initiation 3
• Patients with previous intolerance to iron dextran or iron gluconate 3, 4

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Dosing Regimens

Standard Adult Dosing:

• 200 mg per dose administered as an IV push over 10 minutes without dilution 1
• Maximum single dose: 200 mg 5
• Maximum weekly dose: 500 mg 5
• No test dose required (unlike iron dextran formulations) 1
• Doses given multiple times until calculated total iron requirement is met, typically 5–10 infusions to achieve 1,000–2,000 mg cumulative dose 1

Alternative Administration:

• For doses of 300–500 mg, dilute in maximum 250 mL of 0.9% NaCl 5
• Can be given as slow IV push over 2–5 minutes or infusion over 30–60 minutes 5
• Minimum 7-day interval between doses before reassessing iron parameters 1

Hemodialysis-Specific Protocol:

• 100 mg undiluted IV push over 5 minutes for 10 consecutive dialysis sessions (total ≈1 g) 1
• Maintenance: 100–200 mg directly into hemodialysis line 2–3 times weekly 1
• Administered during dialysis session for convenience 1

Pediatric Dosing (Chronic Kidney Disease):

• <10 kg: 25 mg per dose 1
• 10–20 kg: 50 mg per dose 1
• >20 kg: 100 mg per dose 1

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Expected Therapeutic Effects

Hemoglobin Response:

• Hemoglobin increase of at least 2 g/dL within 4 weeks is the typical therapeutic response 1
• Mean hemoglobin increase of 3.29 g/dL for women and 4.58 g/dL for men 6
• 84–94% of patients respond with hemoglobin increase ≥2 g/dL 6
• Correction of anemia achieved in 68–71% of patients 6

Iron Parameter Targets (Hemodialysis):

• Transferrin saturation (TSAT) ≥20% 1
• Serum ferritin ≥100 ng/mL after therapy 1
• Maintain TSAT <50% and ferritin <800 ng/mL (preferably ≤500 ng/mL) to avoid iron overload 1
• Target hemoglobin: 11–12 g/dL 1

Timing of Response:

• Transferrin and ferritin levels can be measured reliably 48 hours after IV administration 3
• Wait at least 7 days after 200 mg dose before accurate assessment of iron parameters 1

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Monitoring Protocol

Initial Assessment:

• Baseline hemoglobin, ferritin, and transferrin saturation 1
• Monitor vital signs during and after infusion 5

Follow-Up Monitoring:

• Reassess at 4 weeks after final infusion: hemoglobin, ferritin, and transferrin saturation 1
• Complete blood count every 3 months for the first year 1
• Every 6 months for the next 2–3 years 1
• Iron parameters at least once every 3 months in patients receiving ongoing IV iron 1

Safety Monitoring:

• Serum ferritin should not exceed 500 μg/L to avoid iron overload toxicity 1
• Monitor serum phosphate in patients receiving long-term or multiple high-dose infusions 5

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Adverse Reactions

Common Side Effects (Mild):

• Hypotension 1, 5
• Arthralgia and myalgia 1
• Injection site reactions 1
• Nausea, vomiting, and diarrhea 5
• Flushing and abdominal cramps 5
• Headache and dizziness 5
• Pruritus 5

Incidence of Reactions:

• Overall hypersensitivity-type reactions: approximately 0.5% 1, 5
• Anaphylactic reactions: extremely rare (<1:200,000 administrations) 1
• Serious adverse reaction rates are low and similar to oral iron preparations 5

Metabolic Complications:

• Hypophosphatemia occurs in approximately 1% of iron sucrose patients, markedly lower than ferric carboxymaltose (58%) or iron derisomaltose (4%) 1, 5

Serious Adverse Events (Rare):

• Dyspnea, wheezing, hypotension, and chest pain indicate severe reactions 5
• Systemic iron toxicity with hepatocellular damage when doses exceed recommended maximums 5

Management of Infusion Reactions:

• Stop the infusion immediately 5
• Switch to hydration fluid to keep vein open 5
• Monitor patient; most reactions are self-limiting and resolve spontaneously 5
• After 15 minutes, rechallenge may be considered with careful monitoring 5
• If symptoms persist or worsen, administer IV corticosteroid (hydrocortisone) 5
• For anaphylaxis: IV epinephrine, diphenhydramine, and corticosteroids 5

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Safety Considerations and Contraindications

Absolute Contraindications:

• Ongoing bacteremia or uncontrolled infection – withhold until infection is resolved 1
• Active bacteremia 5

Relative Contraindications:

• Acute or chronic infection may be acceptable after risk-benefit assessment 1
• Hemoglobin >15 g/dL 7

Special Precautions:

• Test doses recommended for patients with history of IV iron sensitivities or multiple drug allergies 5
• Resuscitation facilities must be available during administration 1, 5
• Trained personnel for managing infusion reactions required 1
• Increased adverse effects reported in patients with collagen diseases 5

Pregnancy and Pediatric Use:

• Safe in pregnancy with minimal side effects compared to oral iron 2
• Very few serious adverse reactions observed in 232 children receiving 1,624 doses 5

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Advantages Over Other IV Iron Formulations

Compared to Iron Dextran:

• No test dose required (iron dextran requires 25 mg test dose) 1, 5
• Fewer adverse effects, particularly versus high-molecular-weight iron dextran 5
• Markedly lower incidence of life-threatening anaphylactoid reactions 3

Compared to Ferric Carboxymaltose:

• Lower hypophosphatemia risk (1% vs 58%) 1, 5
• Preferred for repeat infusions within 3-month intervals to minimize hypophosphatemia 1
• Ideal for hemodialysis because it can be administered directly through dialysis circuit 1
• Lower cost (£102 per 1,000 mg vs £154–170 for newer formulations) 1

Disadvantages:

• Requires multiple visits (typically 5–10 infusions) versus single-dose formulations 1
• Maximum 200 mg per dose versus 1,000 mg for ferric carboxymaltose 1

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Clinical Pitfalls to Avoid

• Do not administer during active bacteremia, though chronic infection alone is not an absolute contraindication 1, 5
• Avoid exceeding maximum single dose of 200 mg to minimize dose-related reactions 5
• Do not recheck iron parameters within 7 days of 200 mg dose – falsely elevated results 1
• Do not exceed serum ferritin of 500 μg/L to prevent iron overload 1
• Ensure resuscitation equipment and trained personnel are immediately available 5
• Monitor vital signs during infusion, starting slowly for first 5 minutes 5

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Practical Administration Tips

• Administer by healthcare professionals trained in managing infusion reactions 1
• Start infusion slowly for first 5 minutes to monitor for reactions 5
• Observe patient for 15–60 minutes after administration 5
• For hemodialysis patients, administer directly into dialysis line for convenience 1
• Iron sucrose is generally well-tolerated with clinically manageable safety profile when using appropriate dosing and monitoring 6