What are the side effects of Iron Dextran (Intravenous Iron)?

Side Effects of Iron Dextran IV

Iron dextran IV can cause serious adverse reactions including potentially fatal anaphylactic reactions, occurring in approximately 0.7% of patients, and should be administered with extreme caution with resuscitation equipment and trained personnel readily available. 1

Common Adverse Reactions

Iron dextran administration is associated with a range of adverse effects that can be categorized as follows:

Immediate/Acute Reactions

• Anaphylactic/anaphylactoid reactions:

  • Occur within minutes of administration
  • Characterized by respiratory difficulty and/or cardiovascular collapse
  • Fatal in some cases
  • Incidence: 0.7% of patients experience serious reactions 2
  • Risk factors: history of drug allergies (2.4x higher risk) and multiple drug allergies (5.5x higher risk) 3

• Cardiovascular effects:

  • Chest pain, chest tightness
  • Hypotension or hypertension
  • Tachycardia or bradycardia
  • Flushing (particularly with rapid IV administration)
  • Arrhythmias, shock, cardiac arrest 1

• Respiratory effects:

  • Dyspnea, bronchospasm, wheezing
  • Respiratory arrest 1

• Other immediate reactions:

  • Urticaria, pruritus, rash
  • Abdominal pain, nausea, vomiting
  • Headache, dizziness, paresthesia 1

Delayed Reactions

• Typically occur 24-48 hours after administration
• Usually subside within 3-4 days
• More common with larger doses (such as total dose infusions)
• Symptoms include:
  • Arthralgia, backache, myalgia
  • Fever, chills
  • Headache, malaise
  • Nausea, vomiting 1

Mechanism of Adverse Reactions

The mechanisms behind iron dextran reactions include:

1. Type I (IgE-mediated) anaphylactic reactions caused by preformed dextran antibodies
2. Type I anaphylactoid reactions from transient overload of transferrin binding capacity
3. Immune complex activation by specific IgG antibodies 2

Risk Factors and Special Populations

• Patients with increased risk:
  • History of drug allergies, especially multiple drug allergies 3
  • Patients with collagen diseases 2
  • Patients with serious liver impairment 1
  • Patients with pre-existing cardiovascular disease 1
  • Patients with acute infectious kidney disease 1

Comparative Safety Profile

• Low molecular weight iron dextran has fewer adverse effects than high molecular weight iron dextran 2
• More recently introduced iron compounds (iron sucrose, iron gluconate, iron carboxymaltose) have fewer adverse effects than iron dextran 2
• In a study of IBD patients, adverse event rates per 1000 infusions were:
  • Ferumoxytol: 2.54
  • Ferric gluconate: 1.85
  • Iron sucrose: 1.74
  • Iron dextran: 0.96 4
• Iron sucrose has been shown to be safe in patients with documented sensitivity to iron dextran 5

Risk Mitigation Strategies

1. Test dose administration:

   • Administer a test dose of 0.5 mL before therapeutic dosing
   • Observe patients for at least one hour before administering the full dose
   • Note that fatal reactions have occurred even after a tolerated test dose 1

2. Pre-treatment protocol for patients with previous allergic reactions:

   • Methylprednisolone
   • Diphenhydramine
   • Ephedrine 2

3. Dosing considerations:

   • Maximum daily dose should not exceed 2 mL undiluted iron dextran 1
   • Smaller doses (100 mg or less) are associated with fewer delayed reactions 2
   • Avoid rapid infusion to prevent flushing and hypotension 1

4. Monitoring:

   • Always have resuscitation equipment and trained personnel available
   • Monitor vital signs during and after administration
   • Observe for signs of anaphylaxis during administration 1

Alternative Iron Preparations

For patients at high risk of reactions to iron dextran, consider alternative IV iron formulations:

• Iron sucrose (safer in iron dextran-sensitive patients) 5
• Iron gluconate
• Iron carboxymaltose 2

These newer preparations generally have better safety profiles with lower rates of serious adverse reactions compared to iron dextran.