What is the recommended dose of intravenous (IV) ferric carboxymaltose (iron supplement)?

Ferric Carboxymaltose Dosing

In the United States, ferric carboxymaltose is administered as 750 mg per dose, with two doses given at least 7 days apart (total 1,500 mg), while in Europe and Asia, it is routinely given as a single 1,000 mg infusion. 1, 2, 3

Standard Dosing Regimens

United States FDA-Approved Dosing

• 750 mg per dose (maximum single dose) 1, 2, 3
• Administer two doses separated by at least 7 days 1, 2, 3
• Total cumulative dose: 1,500 mg 3
• Alternative calculation: 15 mg/kg body weight up to maximum 750 mg per dose 3

European/Asian Dosing

• 1,000 mg as a single infusion 1, 2
• This approach is standard practice throughout Europe and Asia 1

Administration Protocol

Preparation and Infusion

• Dilute in 100 mL of normal saline 1, 2
• Infuse over 20-30 minutes 1, 2
• Observe patients for at least 30 minutes post-infusion for adverse reactions 2

Alternative Rapid Administration

Recent research demonstrates that undiluted rapid bolus injection (over minutes rather than 15-30 minutes) is well-tolerated, though this is not yet standard practice 4. This approach showed no serious adverse events in 121 patients but commonly caused transient flushing during injection 4.

Monitoring Parameters

Timing of Laboratory Assessment

• Do NOT check iron parameters within 4 weeks of administration, as circulating iron interferes with assays and produces spurious results 1, 2
• Check CBC and iron parameters (ferritin, transferrin saturation) at 4-8 weeks after the last infusion 1, 2
• Hemoglobin should increase 1-2 g/dL within 4-8 weeks of therapy 1, 2

Target Parameters

• Goal ferritin: ≥50 ng/mL (in absence of inflammation) 1
• Transferrin saturation: ≥20% 1

Critical Contraindications and Cautions

Absolute Contraindications

• Hemoglobin >15 g/dL 2, 5
• Hypersensitivity to ferric carboxymaltose or excipients 2, 5
• Anemia not attributed to iron deficiency 2, 5
• Evidence of iron overload 2, 5

Important Caution: Hypophosphatemia Risk

Ferric carboxymaltose should be avoided in patients requiring repeat infusions due to treatment-emergent hypophosphatemia 1, 2. The hypophosphatemia rate with ferric carboxymaltose is 58% compared to 4% with ferric derisomaltose and 1% with iron sucrose 2. Most cases are biochemically moderate (serum phosphate 0.32-0.64 mmol/L) and asymptomatic, resolving without intervention 2.

Use With Caution In:

• Acute or chronic infection (stop treatment in bacteremia) 2, 5
• Known drug allergies, especially severe asthma, eczema, or atopic allergies 2, 5
• Immune or inflammatory conditions 5

Frequency of Repeat Dosing

The frequency depends on the underlying etiology 1:

• Single total dose infusion suffices if the cause of iron deficiency has been eliminated 1
• Multiple administrations necessary for ongoing losses (heavy menstrual bleeding, angiodysplasia, inflammatory bowel disease) or malabsorption conditions (bariatric surgery, autoimmune gastritis, celiac disease) 1

Clinical Efficacy

Ferric carboxymaltose demonstrates superior efficacy compared to oral iron 3, 6:

• 60.4% of patients achieve hemoglobin increase ≥1 g/dL versus 34.7% with oral iron 6
• Mean hemoglobin increase: 0.95 g/dL versus 0.50 g/dL with oral iron at Day 42 6
• First IV iron formulation associated with fewer cardiovascular events and hospitalizations in heart failure patients with iron deficiency 1, 2

Practical Advantages

• Can deliver up to 750-1,000 mg in 15-30 minutes 2, 7
• Requires fewer clinic visits compared to iron sucrose (which requires multiple 200 mg doses) 2, 8
• Better tolerated than oral iron, primarily due to lower gastrointestinal adverse effects 9, 7, 6
• Treatment-related adverse events: 2.7% with ferric carboxymaltose versus 26.2% with oral iron 6