What is the management for an allergic reaction to an iron infusion?

Management of Allergic Reactions to IV Iron Infusions

For allergic reactions to IV iron infusions, immediately stop the infusion, switch to normal saline at KVO rate, and manage based on reaction severity, with epinephrine being the first-line treatment for severe reactions. 1

Classification and Immediate Response

Reactions to IV iron can be classified into three categories:

1. Mild Reactions

• Presentation: Pruritus, flushing, urticaria without other symptoms
• Management:
  • Stop infusion immediately
  • Switch to normal saline at KVO rate
  • Monitor vital signs for ≥15 minutes
  • Consider second-generation antihistamines for urticaria
  • May rechallenge at 50% of initial infusion rate if symptoms resolve 1

2. Moderate Reactions

• Presentation: Hypotension without shock, mild hypoxemia, chest tightness
• Management:
  • Stop infusion immediately
  • Switch to normal saline at KVO rate
  • Consider IV corticosteroids (equivalent dose to 1-2 mg/kg methylprednisolone)
  • Provide oxygen by mask or nasal cannula for hypoxemia
  • H1/H2 antagonists: diphenhydramine 50 mg IV plus ranitidine 50 mg IV 2, 1

3. Severe Reactions/Anaphylaxis

• Presentation: Hypotension with shock, significant hypoxemia, loss of consciousness
• Management:
  • Stop infusion immediately
  • Call emergency services
  • Administer epinephrine 0.3-0.5 mg (0.3-0.5 mL of 1:1000) IM in anterolateral thigh for adults ≥30 kg
  • For children <30 kg: 0.01 mg/kg (0.01 mL/kg) IM, maximum 0.3 mg
  • May repeat every 5-10 minutes as necessary 3
  • Aggressive fluid resuscitation: Normal saline 1-2 L IV at 5-10 mL/kg in first 5 minutes
  • H1/H2 antagonists: diphenhydramine 50 mg IV plus ranitidine 50 mg IV
  • Corticosteroids: 1-2 mg/kg IV methylprednisolone every 6 hours
  • Consider albuterol nebulizer for bronchospasm 2, 1

Critical Management Pearls

1. Epinephrine is first-line for severe reactions - Do not delay administration when anaphylaxis is suspected 2, 3

2. Avoid first-generation antihistamines for minor reactions - They may convert minor reactions into hemodynamically significant events 1

3. Monitor injection sites - Do not administer repeated epinephrine injections at the same site to avoid tissue necrosis 3

4. Observation period - Monitor vital signs until resolution; 24-hour observation recommended for severe reactions 2

5. Documentation - Record reaction details including symptoms, timing, interventions, and response 1

Risk Factors for Reactions

• Previous reaction to IV iron
• Fast iron infusion rate
• Multiple drug allergies
• Severe atopy
• Systemic inflammatory diseases
• Asthma
• Mastocytosis 1, 4

Prevention Strategies

1. Pre-infusion assessment - Screen for risk factors and history of previous reactions 2

2. Appropriate preparation - Have resuscitation equipment and medications readily available 2

3. Proper administration - Administer at appropriate rate according to specific iron formulation 5

4. Trained personnel - Ensure staff are trained in recognition and management of infusion reactions 6

5. Consider alternative formulations - For patients with history of reactions, different iron formulations may be considered 4

Patient Education

Inform patients about possible delayed reactions (flu-like symptoms, arthralgias, myalgias, fever) which typically can be managed with NSAIDs. Advise patients to seek medical attention if symptoms persist beyond 24 hours 1.

Common Pitfalls to Avoid

1. Misclassifying reaction severity - Underestimating severity can delay appropriate treatment

2. Delaying epinephrine - For anaphylaxis, epinephrine is the cornerstone of treatment and should not be delayed

3. Inadequate monitoring - Even mild reactions require close observation as they can progress

4. Inappropriate rechallenge - Severe reactions generally contraindicate rechallenge 2

5. Failing to recognize complement activation-related pseudo-allergy (CARPA) - This is more common than true IgE-mediated reactions with newer iron formulations 5