How to administer iron sucrose (intravenous iron) in patients with impaired renal (kidney) function?

Iron Sucrose Administration in Reduced Kidney Function

Iron sucrose should be administered intravenously in doses of 100 mg for hemodialysis patients (given over 2-5 minutes or diluted over 15 minutes), 200 mg for non-dialysis CKD patients, and 300-400 mg for peritoneal dialysis patients, with no test dose required and no dose adjustment needed for renal impairment. 1

Administration Protocol by CKD Population

Hemodialysis-Dependent CKD (HDD-CKD)

For adult hemodialysis patients:

• Administer 100 mg undiluted as slow IV injection over 2-5 minutes, OR dilute in maximum 100 mL of 0.9% NaCl and infuse over at least 15 minutes 1
• Give during each consecutive hemodialysis session, typically early in the session (within first hour) 2
• Total treatment course is 1000 mg (10 doses of 100 mg over 10 weeks) 3, 1
• For maintenance therapy after achieving target iron levels, continue 25-125 mg weekly 2

For pediatric hemodialysis patients (≥2 years):

• Maintenance dosing: 0.5 mg/kg (not exceeding 100 mg per dose) every 2 weeks for 12 weeks 1
• Can be given undiluted over 5 minutes or diluted in 0.9% NaCl at 1-2 mg/mL concentration over 5-60 minutes 1

Critical safety consideration: The 100 mg dose limit per session minimizes arthralgias and myalgias that occur with higher doses 2. Doses larger than 100 mg given at one time are not recommended by the manufacturer for this population 3.

Non-Dialysis Dependent CKD (NDD-CKD)

For adult NDD-CKD patients:

• Administer 200 mg undiluted as slow IV injection over 2-5 minutes, OR dilute in maximum 100 mL of 0.9% NaCl over 15 minutes 1
• Give on 5 different occasions over a 14-day period (total 1000 mg) 1
• Alternative regimen: 500 mg diluted in maximum 250 mL of 0.9% NaCl over 3.5-4 hours on Day 1 and Day 14, though this has limited experience 1

For pediatric NDD-CKD patients (≥2 years) on erythropoietin:

• Maintenance dosing: 0.5 mg/kg (not exceeding 100 mg per dose) every 4 weeks for 12 weeks 1
• Administration method same as pediatric hemodialysis patients 1

Peritoneal Dialysis-Dependent CKD (PDD-CKD)

For adult PDD-CKD patients:

• Give 3 divided doses within a 28-day period: 1
  • Two 300 mg infusions over 1.5 hours each, 14 days apart
  • One 400 mg infusion over 2.5 hours, 14 days after the second dose
• Dilute in maximum 250 mL of 0.9% NaCl 1

For pediatric PDD-CKD patients (≥2 years) on erythropoietin:

• Same dosing as pediatric NDD-CKD: 0.5 mg/kg every 4 weeks for 12 weeks 1

Key Safety Considerations

No Test Dose Required

Iron sucrose does NOT require a test dose, unlike iron dextran which carries anaphylaxis risk 3, 4. This is a critical distinction—iron sucrose has a superior safety profile with fewer adverse effects than iron dextran 3.

Dose-Related Safety Limits

Research demonstrates clear dose thresholds for adverse reactions:

• 200-300 mg doses over 2 hours are safe with no adverse events in large studies 5
• 400 mg doses showed adverse reactions in 2 of 35 patients (hypotension, nausea, lower back pain) 5
• 500 mg doses caused reactions in 8 of 22 patients (dizziness, hypotension, nausea) and should be avoided 5

Critical pitfall: One case of systemic iron toxicity with hepatocellular damage occurred in a pediatric patient receiving 16 mg/kg of iron sucrose, emphasizing the importance of not exceeding recommended maximum doses 3.

Risk of Free Iron Formation

If transferrin levels are <180 mg/dL, free iron may occur with 100 mg doses of iron sucrose 3. Lower doses (10,20, or 40 mg) do not result in free iron formation 3. This is particularly relevant in patients with low body mass or low transferrin levels 6.

Common Adverse Reactions

• Hypotension, flushing, arthralgias, myalgias, and headache are the most common reactions 2
• Reactions are typically mild and self-limited 3
• Most reactions represent CARPA (complement-activated related pseudo-allergy), not true anaphylaxis 2
• Anaphylaxis occurs in less than 1:200,000 administrations with modern formulations 2

Monitoring Parameters

Timing of Laboratory Assessment

The timing of iron parameter measurement depends on the dose administered:

• For doses ≤100-125 mg weekly: measure iron parameters without interrupting therapy 2
• For doses of 200-500 mg: wait at least 7 days before measuring 2
• For doses ≥1000 mg: wait at least 2 weeks for accurate assessment 2

Target Iron Levels

• Maintain transferrin saturation (TSAT) ≥20% 3, 4
• Maintain serum ferritin ≥100 ng/mL for non-dialysis patients, ≥200 ng/mL for hemodialysis patients 4
• Avoid iron overload: do not administer if TSAT >50% and/or ferritin >800 ng/mL 3, 2

Monitoring Frequency

• During initiation of erythropoietin therapy: check TSAT and ferritin monthly in patients not receiving IV iron 3
• In patients receiving IV iron: check at least once every 3 months 3

Clinical Context and Rationale

Why IV Iron is Superior in CKD

Oral iron usually cannot maintain adequate iron stores in hemodialysis patients treated with erythropoietin 3, 4. This occurs because:

• Iron losses are high in hemodialysis (blood losses during dialysis) 3
• Erythropoietin stimulates erythropoiesis beyond normal levels, creating functional iron deficiency 3
• Elevated hepcidin levels in CKD impair intestinal iron absorption 4

Research confirms this: among early non-responders to oral iron, only 21% respond to additional oral therapy versus 65% who respond to IV iron 4. In comparative studies, IV iron patients achieved hemoglobin >11.0 g/dL more often (54.2%) than oral iron patients (31.3%) 7.

When to Repeat Treatment

Treatment may be repeated if iron deficiency recurs 1. Regular use of small doses of IV iron, particularly in hemodialysis patients, prevents iron deficiency and promotes better erythropoiesis than oral iron therapy 3.

Special Populations and Contraindications

Active Infection

Withhold IV iron during active bacteremia 2. However, IV iron can be administered during inflammation (as opposed to acute infection) 8.

Inflammatory Conditions

In inflammatory conditions like inflammatory bowel disease, IV iron may be more effective than oral iron due to hepcidin-mediated inhibition of oral iron absorption 2.

Patients on ACE Inhibitors

Use caution in patients receiving ACE inhibitors, as case reports describe abdominal cramps and hypotension with iron gluconate in this population 3. While this was reported with iron gluconate rather than iron sucrose, vigilance is warranted.