What is the recommended dosing of Venofer (iron sucrose) for an adolescent patient with hypoferritinemia and a weight of 84.2 kg?

Venofer Dosing for Adolescent with Severe Iron Deficiency

For an 84.2 kg adolescent with a ferritin of 9 ng/mL, administer Venofer 0.5 mg/kg (approximately 42 mg, rounded to 50 mg for practical dosing) undiluted by slow intravenous injection over 5 minutes, repeated every 2-4 weeks for iron maintenance, with close monitoring to avoid exceeding ferritin levels of 500 ng/mL. 1

Dosing Algorithm Based on FDA Label and Clinical Context

Pediatric Dosing (Age ≥2 years)

The FDA-approved dosing for adolescents depends on the underlying condition 1:

• For hemodialysis-dependent CKD (HDD-CKD): 0.5 mg/kg (not to exceed 100 mg per dose) every 2 weeks for 12 weeks 1
• For non-dialysis or peritoneal dialysis CKD on erythropoietin: 0.5 mg/kg (not to exceed 100 mg per dose) every 4 weeks for 12 weeks 1

For this 84.2 kg patient: 0.5 mg/kg = 42.1 mg, which can be rounded to 50 mg for practical administration 1

Administration Method

Venofer can be given either 1:

• Undiluted by slow IV injection over 5 minutes (preferred for smaller doses)
• Diluted in 0.9% NaCl at 1-2 mg/mL concentration over 5-60 minutes (do not dilute below 1 mg/mL) 1

Critical Safety Considerations for Adolescents

Ferritin Monitoring Thresholds

With a baseline ferritin of 9 ng/mL, this patient has severe absolute iron deficiency requiring aggressive repletion, but ferritin must be monitored to prevent iron overload. 2

• Target ferritin range: Aim for 100-500 ng/mL 2
• Upper safety limit: Do not exceed 500 ng/mL in children and adolescents to avoid toxicity 2
• Monitoring frequency: Check ferritin every 3 months during treatment 2

Adolescent-Specific Iron Requirements

Adolescents have substantially increased iron demands due to rapid growth and blood volume expansion 2:

• Males require approximately 0.2 mg/kg/day of iron 2
• Females require approximately 0.35 mg/kg/day due to menstrual losses 2
• During puberty, blood volume increases by approximately 1900 mL, requiring ~1000 mg of iron for erythropoiesis alone 2

Treatment Course Calculation

Total Iron Deficit Estimation

For severe iron deficiency (ferritin 9 ng/mL), the total cumulative dose should be calculated based on hemoglobin deficit and iron store repletion 2:

• Typical total course: 1000 mg for adults with severe deficiency 1
• For this 84.2 kg adolescent: Proportionally, approximately 600-800 mg total may be needed
• Dosing schedule: Repeat doses every 3-7 days until total dose administered 2

Practical Dosing Schedule

Recommended approach:

1. Start with 50 mg IV every 2 weeks 1
2. Continue for 12 weeks (6 doses = 300 mg total) 1
3. Recheck ferritin, hemoglobin, and transferrin saturation 2
4. If ferritin remains <100 ng/mL, continue treatment 2
5. If ferritin reaches 100-500 ng/mL, switch to maintenance dosing every 4 weeks 1

Alternative Considerations

Oral Iron Trial First

Before committing to IV iron, consider initial oral iron therapy 2:

• Oral dose: 60 mg elemental iron daily for adolescents 2
• Trial duration: 4 weeks 2
• Success criteria: Hemoglobin increase ≥1 g/dL confirms response 2
• If oral fails: Proceed to IV iron as outlined above 2

When to Use Higher Doses

The standard pediatric dose of 0.5 mg/kg may be insufficient for rapid correction. If this patient has symptomatic anemia requiring urgent correction, consider 1:

• Doses up to 100 mg per administration (the maximum single pediatric dose) 1
• More frequent dosing (every 2 weeks rather than every 4 weeks) 1

Common Pitfalls to Avoid

Do Not Overdose Based on Adult Protocols

Adult dosing for Venofer ranges from 100-500 mg per dose 1, but pediatric patients should not exceed 100 mg per dose regardless of weight 1. The 0.5 mg/kg dosing with a 100 mg cap is specifically designed for safety in younger patients 1.

Monitor for Functional Iron Deficiency

Even with ferritin >100 ng/mL, functional iron deficiency may persist if transferrin saturation remains <20% 2. Continue iron therapy if TSAT <20% despite adequate ferritin, but do not exceed ferritin of 500 ng/mL 2.

Avoid Iron During Acute Infection

Temporarily withhold IV iron if acute infection develops, as iron can impair immune function 3. Resume after complete recovery 3.

Test Dose Considerations

While the FDA label for iron sucrose (Venofer) does not mandate a test dose like iron dextran 2, ensure emergency medications (epinephrine, diphenhydramine, corticosteroids) are immediately available 2. Observe the patient for 15-60 minutes after the first dose 2.