What is the appropriate intravenous iron sucrose dosing schedule for an adult with iron‑deficiency anemia?

Iron Sucrose Intravenous Dosing

For adult iron-deficiency anemia, administer iron sucrose 200 mg intravenously over 30 minutes, repeated 2–3 times weekly until the total calculated iron deficit is replaced—typically 1,000–1,500 mg total dose delivered over 5–7 visits. 1

Standard Dosing Protocol

• Maximum single dose: 200 mg per injection 2, 1
• Maximum weekly dose: 500 mg 1
• Infusion time: Minimum 30 minutes for 200 mg 2
• Alternative rapid administration: 200 mg slow IV push over 2–5 minutes is licensed and more convenient than prolonged infusion 1
• Dilution for higher doses: For 300–500 mg weekly doses, dilute in maximum 250 mL of 0.9% NaCl 1

The British Society of Gastroenterology confirms iron sucrose requires 4–7 visits to achieve full iron repletion, in contrast to newer total-dose formulations that accomplish this in 1–2 infusions 1. This multi-visit requirement is the primary practical disadvantage of iron sucrose compared to ferric carboxymaltose or ferric derisomaltose 2.

Test Dose Requirements

• No routine test dose required for iron sucrose, distinguishing it from high-molecular-weight iron dextran 1, 3
• Consider test dose (25 mg slow IV push, observe before proceeding) only for patients with history of IV iron sensitivities or multiple drug allergies 1

Administration and Monitoring

• Start infusion slowly for the first 5 minutes to monitor for reactions 1
• Observe patient for at least 30 minutes after infusion completion 1
• Ensure resuscitation equipment and trained personnel are immediately available during administration 1
• Monitor vital signs during and after infusion 1

Iron sucrose does not require the prolonged observation mandated for iron dextran because hypersensitivity reactions occur in only approximately 0.5% of patients 1, significantly lower than iron dextran but slightly higher than oral preparations 1.

Absolute Contraindications

• Active bacteremia: Withhold iron sucrose in patients with ongoing bloodstream infection 1
• Hemoglobin >15 g/dL: Do not administer 1
• Known hypersensitivity to iron sucrose or its excipients 1

Chronic infection alone is not an absolute contraindication if risk/benefit favors treatment 1.

Expected Hemoglobin Response

• Reticulocytosis begins 3–5 days post-administration 4
• Hemoglobin increase of approximately 1 g/dL within 2 weeks in responding patients 1
• Significant improvement first evident after three 100 mg doses and persisting at least 5 weeks after completion 4

In the North American clinical trial, iron sucrose administered as 1,000 mg in 10 divided doses (100 mg each) produced significant sustained increases in hemoglobin, transferrin saturation, and ferritin levels 4.

Follow-Up and Re-Evaluation

• Recheck hemoglobin at 4 weeks to confirm adequate response 2
• Do not recheck iron parameters within 4 weeks of administration, as circulating iron interferes with assays 1
• Continue monitoring every 3 months for 12 months, then 6-monthly for 2–3 years to detect recurrent deficiency 2

Safety Profile and Adverse Effects

• Hypersensitivity reactions: Approximately 0.5% incidence 1
• Common systemic effects: Hypotension, nausea, vomiting, diarrhea 1
• Musculoskeletal reactions: Arthralgia, myalgia, back pain (usually transient) 1
• Hypophosphatemia: Occurs in only 1% of iron sucrose patients, compared to 58% with ferric carboxymaltose 2, 1

Iron sucrose demonstrates fewer adverse effects than iron dextran formulations, particularly high-molecular-weight iron dextran 1.

Management of Infusion Reactions

• For minor reactions: Stop infusion, switch to hydration fluid to keep vein open, monitor 1
• Most reactions are self-limiting and resolve spontaneously with continued monitoring 1
• After 15 minutes: Consider rechallenge with careful monitoring 1
• If symptoms persist or worsen: Administer IV corticosteroid (e.g., hydrocortosone) 1
• For severe reactions (dyspnea, wheezing, hypotension, chest pain): Treat with IV epinephrine, diphenhydramine, and corticosteroids 1

Pediatric Dosing

• FDA-approved for children ≥2 years of age 1
• Dose: 7 mg/kg (maximum 200 mg) IV per dose, given 2–3 times weekly 1, 5
• Total cumulative dose: 600–1,200 mg depending on severity and calculated iron deficit 1
• Safety data: Very few serious adverse reactions observed in 232 children receiving 1,624 doses 1

In a single-institution study, iron sucrose raised hemoglobin from 7.6±2.38 g/dL to 12.4±0.64 g/dL within 31–42 days in children with IDA who failed oral therapy 5.

Total Dose Infusion Protocol

Although not standard practice, total dose infusion (TDI) of iron sucrose in doses ≥300 mg has been studied:

• Mean total dose: 680 mg (range 300–2,500 mg) 6
• Single high-dose: 7 mg iron/kg body weight (not exceeding 500 mg) infused over 3.5 hours 7
• Safety: Well tolerated with nausea being most common adverse effect (2.9%) 6
• Efficacy: Mean hemoglobin increase of 2.1 g/dL 6

However, this approach exceeds standard guideline recommendations and should only be considered in specialized settings with appropriate monitoring 1.

Key Clinical Pitfalls to Avoid

• Do not exceed 200 mg single dose in routine practice to minimize dose-related anaphylactoid reactions 1
• Do not administer during active bacteremia, though chronic infection alone is not an absolute contraindication 1
• Do not recheck ferritin within 4 weeks of administration, as falsely elevated levels mask inadequate repletion 1
• Do not assume all infusion reactions are anaphylaxis—most are complement activation-related pseudo-allergy (CARPA) that resolve without epinephrine 1

When to Choose Alternative IV Iron Formulations

Consider ferric carboxymaltose or ferric derisomaltose instead of iron sucrose when:

• Rapid repletion needed: Single 1,000 mg infusion over 15 minutes versus 5–7 visits for iron sucrose 2, 1
• Patient convenience prioritized: 1–2 total infusions versus 4–7 visits 1
• Severe anemia (Hgb <10 g/dL): Faster correction achievable 8

Iron sucrose remains appropriate when cost is a primary concern (£102 per 1,000 mg versus £154–170 for newer formulations) 2 or when hypophosphatemia risk must be minimized 1.