What are the common intravenous (IV) iron formulations used to treat iron deficiency?

Common Intravenous Iron Formulations for Iron Deficiency

The most commonly used IV iron formulations are iron sucrose (Venofer), ferric carboxymaltose (Ferinject/Injectafer), ferric derisomaltose/iron isomaltoside 1000 (Monofer), ferric gluconate (Ferrlecit), and ferrumoxytol, with selection based on dosing convenience, safety profile, and clinical context. 1

Primary IV Iron Formulations

Iron Sucrose (Venofer)

• Maximum single dose is 200 mg, administered as an IV push over 10 minutes 1, 2
• Requires multiple doses (typically 5 rounds of 200 mg each over 14 days for a total of 1000 mg) to achieve full iron repletion 2, 3
• Large published trials in IBD patients demonstrate safety and efficacy 1
• No test dose required, unlike iron dextran preparations 1, 3
• Resuscitation facilities must be immediately available during all infusions 2

Ferric Carboxymaltose (Ferinject/Injectafer)

• Allows high single doses of 500-1000 mg (up to 20 mg/kg body weight) 1
• Can be delivered within 15 minutes, providing significant logistic advantage 1, 4
• Rapidly improves hemoglobin levels and replenishes depleted iron stores 4, 5
• Major caveat: Associated with hypophosphatemia in 50-74% of patients due to elevated FGF-23, which can cause bone pain, osteomalacia, and fractures with repeated use 6, 7, 8
• Hypophosphatemia severity correlates with FCM dose and may persist for 6 months 8

Ferric Derisomaltose/Iron Isomaltoside 1000 (Monofer)

• Allows complete iron repletion in a single infusion with doses up to 20 mg/kg 9
• Significantly lower risk of hypophosphatemia compared to ferric carboxymaltose, making it a safer option for repeated dosing 9, 6
• Administered as an IV infusion over 15-30 minutes 9
• No test dose required 9
• Large published trials in IBD patients demonstrate efficacy 1

Ferric Gluconate (Ferrlecit)

• Maximum single dose is 125 mg of elemental iron 10
• Typically administered over 60 minutes for the 125 mg dose 10
• Terminal elimination half-life approximately 1-1.5 hours 10
• Contains benzyl alcohol (9 mg/mL) as inactive ingredient 10
• Commonly used in hemodialysis patients at 100-200 mg per dialysis session 10

Ferrumoxytol

• Licensed for use in chronic kidney disease 1
• Currently undergoing Phase III trials in IBD and other conditions associated with iron deficiency 1
• Small data series available but less extensively studied than other formulations 1

Formulations to Avoid

Iron Dextran

• Requires mandatory test dose due to risk of serious anaphylactic reactions (0.6-0.7% incidence) 1
• 31 fatalities reported between 1976 and 1996 1
• Can deliver up to 20 mg/kg in single infusion over 6 hours, but safety concerns limit use 1
• Modern non-dextran formulations are strongly preferred 1, 5

Intramuscular Iron

• Obsolete and should not be used—injections are painful, damaging to tissues, and associated with unacceptable side effects 1

Practical Selection Algorithm

For patients requiring rapid, complete iron repletion in single infusion:

• Choose ferric derisomaltose (preferred due to lower hypophosphatemia risk) 9, 6
• Alternative: ferric carboxymaltose if ferric derisomaltose unavailable, but monitor phosphate levels 1, 6

For patients with inflammatory bowel disease or active inflammation:

• IV iron is first-line over oral iron 1
• Iron sucrose, ferric carboxymaltose, or ferric derisomaltose all have large published trials demonstrating efficacy 1

For hemodialysis patients:

• Iron sucrose 100-200 mg or ferric gluconate 125 mg administered 2-3 times weekly into dialysis line 3, 10

For patients requiring multiple smaller doses:

• Iron sucrose 200 mg over 10 minutes is most convenient 1, 2

Critical Safety Considerations

• All IV iron formulations carry risk of severe infusion reactions (<1% in prospective trials), requiring immediate availability of resuscitation equipment 1, 6, 7
• Hypersensitivity reactions are usually non-allergic Complement Activation-Related Pseudo-Allergy (CARPA), reduced by slow infusion rates 6
• Avoid exceeding transferrin saturation >50% or ferritin >800 μg/L to prevent iron overload 1
• Never administer IV iron during active bacterial infection 3
• With ferric carboxymaltose, monitor serum phosphate at baseline and post-treatment due to high hypophosphatemia risk 6, 7, 8