Infed - Drug Monograph

Introduction

Infed (iron dextran injection) is a parenteral iron preparation used for the treatment of iron deficiency anemia when oral iron therapy is ineffective or impractical. It contains a complex of ferric hydroxide and dextran in a colloidal solution, allowing for direct intravenous or intramuscular administration of iron.

Mechanism of Action

Infed provides a source of elemental iron that is directly available for incorporation into hemoglobin. Following administration, the iron-dextran complex is taken up by the reticuloendothelial system, where the iron is released from the dextran component and becomes bound to transferrin for transport to bone marrow. This iron is then utilized for erythropoiesis, increasing hemoglobin production and correcting iron deficiency.

Indications

• Treatment of iron deficiency anemia when oral iron administration is unsatisfactory or impossible
• Patients who cannot tolerate oral iron preparations
• Patients with gastrointestinal disorders that impair iron absorption
• Patients requiring rapid iron repletion (e.g., preoperative preparation, postpartum anemia)
• Patients with chronic blood loss who cannot be maintained on oral iron

Dosage and Administration

Where LBW = lean body weight (kg)

• Intramuscular: Use Z-track technique, deep injection into upper outer quadrant of gluteus maximus
• Intravenous: Slow infusion after test dose administration

• Pediatric: 0.5 mL (25 mg iron) initially, then increase gradually
• Renal impairment: No dosage adjustment required
• Hepatic impairment: Use with caution

Pharmacokinetics

Contraindications

• Hypersensitivity to iron dextran or any component of the formulation
• Non-iron deficiency anemias
• Evidence of iron overload
• History of anaphylaxis to parenteral iron products
• Patients with active acute or chronic infection (unless concurrently treated with antibiotics)

Warnings and Precautions

• Delayed reactions (arthralgia, myalgia, fever) may occur 24-48 hours after administration
• Use with caution in patients with rheumatoid arthritis—may exacerbate joint pain and swelling
• Potential for carcinogenicity based on animal studies
• May cause hypotension; administer slowly during IV infusion
• Hemosiderosis risk with repeated administration

Drug Interactions

• Oral iron preparations: Concurrent use may lead to iron overload
• Dimercaprol: May form toxic complexes with iron
• Chloramphenicol: May delay iron utilization
• ACE inhibitors: Potential for exacerbated anaphylactoid reactions
• Other parenteral iron products: Increased risk of adverse effects

Adverse Effects

• Headache (12%)
• Fever (3%)
• Nausea (3%)
• Arthralgia/myalgia (2%)
• Hypotension (2%)
• Flushing (1%)

• Anaphylaxis (0.6-0.7%)
• Severe hypotension
• Seizures
• Arthritic exacerbation
• Lymphadenopathy
• Phlebitis at injection site
• Sterile abscesses (IM administration)
• Brown skin discoloration (IM administration)

Monitoring Parameters

• Prior to therapy: Complete blood count, iron studies (ferritin, transferrin saturation), renal function
• During administration: Vital signs every 5-15 minutes during infusion
• Post-administration: Monitor for delayed reactions for 48 hours
• Follow-up: Hemoglobin response at 2-4 weeks, iron stores at 3 months
• Long-term: Monitor for iron overload with repeated dosing

Patient Education

• Report any signs of allergic reaction immediately (hives, itching, swelling, difficulty breathing)
• Be aware of potential delayed reactions (joint pain, muscle pain, fever) occurring 1-2 days after injection
• Do not take oral iron supplements unless directed by healthcare provider
• Understand that urine may darken for 1-2 days after administration (normal phenomenon)
• Report any pain, redness, or swelling at injection site
• Keep all follow-up appointments for monitoring
• Inform all healthcare providers about Infed administration history

References

1. FDA Prescribing Information: Infed (iron dextran injection) 2. Auerbach M, Ballard H. Clinical use of intravenous iron: administration, efficacy, and safety. Hematology Am Soc Hematol Educ Program. 2010;2010:338-347. 3. Chertow GM, Mason PD, Vaage-Nilsen O, Ahlmén J. Update on adverse drug events associated with parenteral iron. Nephrol Dial Transplant. 2006;21(2):378-382. 4. Gasche C, Ahmad T, Tulassay Z, et al. Ferric carboxymaltose prevents recurrence of anemia in patients with inflammatory bowel disease. Clin Gastroenterol Hepatol. 2013;11(3):269-277. 5. Rampton D, Folkersen J, Fishbane S, et al. Hypersensitivity reactions to intravenous iron: guidance for risk minimization and management. Haematologica. 2014;99(11):1671-1676. 6. Micromedex Solutions: Iron Dextran. Truven Health Analytics.