What is the management for an allergic reaction to intravenous (IV) iron infusion?

Management of Allergic Reactions to Intravenous 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 Recognition of Reactions

Reactions to IV iron can be classified into three categories:

Mild Hypersensitivity Reactions (HSR)

• Symptoms: Pruritus, flushing, urticaria, chest tightness, back pain, joint pain
• Management: Stop infusion, monitor for ≥15 minutes, maintain IV NS at KVO

Moderate HSR

• Symptoms: Mild reaction plus transient cough, shortness of breath, tachycardia, hypotension
• Management: Same as mild plus consider IV corticosteroids (hydrocortisone 100-500 mg) and H2 antagonist (famotidine 20 mg)

Severe/Life-threatening HSR (Anaphylaxis)

• Symptoms: Sudden onset with rapid intensification, loss of consciousness, significant hypotension, airway angioedema, involvement of multiple organ systems
• Management: Immediate emergency response with epinephrine as first-line treatment 1, 2

Management Algorithm

1. For ANY reaction:

   • STOP the infusion immediately
   • Switch IV line to normal saline at KVO rate
   • Notify physician
   • Perform physical assessment and monitor vital signs 1

2. For mild reactions:

   • Monitor for ≥15 minutes
   • If symptoms resolve, consider rechallenge at 50% of initial infusion rate
   • For symptom-specific treatment:
     • Nausea: Ondansetron 4-8 mg IV
     • Urticaria: Second-generation antihistamine (loratadine 10 mg PO or cetirizine 10 mg IV/PO) 1

3. For moderate reactions:

   • All steps for mild reactions plus:
   • Consider IV corticosteroid (hydrocortisone 200 mg)
   • For hypotension: Recline patient, administer NS bolus 1000-2000 mL
   • For hypoxemia: Provide oxygen by mask or nasal cannula 1

4. For severe reactions/anaphylaxis:

   • Immediately call emergency services/resuscitation team
   • Administer EPINEPHRINE (1 mg/mL) 0.3 mg IM into anterolateral thigh
   • May repeat epinephrine once if needed
   • Consider albuterol nebulizer for bronchospasm
   • Continue aggressive fluid resuscitation 1, 2

Important Considerations

• Avoid first-generation antihistamines (e.g., diphenhydramine) and vasopressors for minor reactions as they may convert minor reactions into hemodynamically significant events 1, 3
• Most reactions are not true allergies but complement activation-related pseudo-allergy (CARPA) triggered by labile free iron 1, 4
• True IgE-mediated hypersensitivity reactions are extremely rare but can be life-threatening 1
• Rechallenge can be considered for mild/moderate reactions after complete resolution of symptoms 1
• Risk factors for reactions include history of severe asthma/eczema, mastocytosis, multiple drug allergies, and prior reaction to IV iron 1, 5

Post-Reaction Management

• Document the reaction in detail, including symptoms, interventions, and response
• For patients with history of severe reactions, consider:
  • Alternative iron formulation with different physicochemical properties 1
  • Desensitization protocol under specialist supervision 6
  • Slower infusion rates for future administrations 1, 7

Patient Education

• Inform patients about possible delayed reactions (flu-like symptoms, arthralgias, myalgias, fever) that may occur hours to days after infusion
• These delayed symptoms can typically be managed with NSAIDs 1
• Advise patients to seek medical attention if symptoms persist beyond 24 hours 1

Remember that the management of iron infusion reactions requires prompt recognition and severity-related interventions by well-trained medical and nursing staff to ensure patient safety.