What is the management for a patient with a history of anaphylactic reactions who experiences a severe reaction to iron dextran (Intravenous Iron) infusion?

Management of Severe Reaction to Iron Dextran

Stop the infusion immediately, administer intramuscular epinephrine 0.3-0.5 mg into the lateral thigh, and initiate aggressive resuscitation with IV fluids and oxygen while calling for emergency assistance. 1

Immediate Emergency Management

First-Line Interventions (Within Seconds)

• Stop the iron dextran infusion immediately and maintain IV access with normal saline to keep the vein open 1
• Administer epinephrine 0.3-0.5 mg (1 mg/mL) intramuscularly into the anterolateral thigh muscle; repeat every 5-15 minutes if needed 1
• Assess ABCs (Airway, Breathing, Circulation) and level of consciousness 1
• Position the patient appropriately: Trendelenburg position for hypotension, sitting upright for respiratory distress, or recovery position if unconscious 1
• Administer high-flow oxygen if respiratory distress or hypoxemia is present 1
• Call for emergency medical assistance immediately 1

Fluid Resuscitation

• Administer normal saline 1-2 L IV rapidly at 5-10 mL/kg in the first 5 minutes 1
• Give crystalloids or colloids in boluses of 20 mL/kg, followed by slower infusion as needed 1

Adjunctive Medications

• Administer H1/H2 antagonists: diphenhydramine 50 mg IV plus ranitidine 50 mg IV (or famotidine 20 mg IV) 1
• Give corticosteroids: hydrocortisone 200 mg IV or equivalent dose of 1-2 mg/kg methylprednisolone IV every 6 hours to prevent biphasic reactions 1

Critical caveat: While H1 antihistamines like diphenhydramine are recommended in anaphylaxis protocols 1, newer evidence suggests avoiding first-generation antihistamines in minor infusion reactions as they can worsen hypotension and tachycardia 1. However, in true anaphylaxis with severe symptoms, they remain part of standard management after epinephrine. 1

Management of Refractory Symptoms

For Persistent Hypotension (After Epinephrine and Fluids)

• Administer dopamine 400 mg in 500 mL at 2-20 μg/kg/min, titrated to clinical response 1
• Alternative vasopressor: vasopressin 25 units in 250 mL (0.1 U/mL) at 0.01-0.04 U/min 1

For Bradycardia

• Give atropine 600 μg IV 1

For Patients on Beta-Blockers

• Administer glucagon 1-5 mg IV infusion over 5 minutes for refractory cardiovascular effects 1

Post-Reaction Monitoring and Documentation

• Monitor vital signs continuously until complete resolution of symptoms 1
• Observe the patient for at least 24 hours after a severe reaction, as biphasic reactions can occur 1
• Document the reaction thoroughly, including timing, symptoms, treatment administered, and response 1

Critical Considerations for Future Iron Therapy

Absolute Contraindication to Re-challenge

• Never re-administer iron dextran to a patient who has experienced a severe anaphylactic reaction 1
• Do not switch to alternative iron dextran formulations (InFeD vs. DexFerrum), as cross-reactivity occurs and patients who react to one formulation should not receive the other 1

Alternative Iron Formulations

• Switch to iron sucrose or ferric gluconate if IV iron is still required, as these have significantly lower rates of severe reactions compared to iron dextran 1, 2, 3
• Iron sucrose has approximately 0.5% incidence of hypersensitivity reactions compared to higher rates with iron dextran 2, 3
• No test dose is required for iron sucrose, making it safer for patients with prior reactions to iron dextran 2, 3

Key Clinical Pitfalls to Avoid

• Do not rely on test doses to predict severe reactions: Most patients who experience severe anaphylactic reactions to iron dextran have successfully received both test doses and multiple therapeutic doses in the past 1
• Avoid aggressive treatment of minor reactions with antihistamines or vasopressors, as this can convert minor infusion reactions into hemodynamically significant events 1
• Do not assume safety based on prior uneventful administrations: Anaphylaxis can occur after multiple successful infusions 1
• Ensure trained personnel and resuscitation equipment are immediately available whenever administering any IV iron formulation 1, 2

Understanding the Reaction Mechanism

Most reactions to iron dextran are complement activation-related pseudo-allergy (CARPA) rather than true IgE-mediated anaphylaxis, though the clinical presentation and management are identical 3, 4. Iron dextran has the highest risk of severe reactions among all IV iron formulations, with life-threatening reactions occurring in approximately 0.65-0.7% of patients 1, 5. Fatalities, while rare, have been documented with iron dextran but not with newer formulations like iron sucrose or ferric gluconate 1.