Do we need to administer adrenaline (epinephrine) when allergic symptoms due to intravenous (IV) antibiotics are present, in anticipation of anaphylaxis?

Management of Allergic Reactions to IV Antibiotics

Adrenaline (epinephrine) should be administered immediately when allergic symptoms due to IV antibiotics are present, without waiting for full anaphylaxis to develop, as early intervention can prevent progression to life-threatening anaphylaxis and improve outcomes. 1

Assessment and Classification of Allergic Reactions

Allergic reactions to IV antibiotics can be classified by severity:

• Grade I: Cutaneous signs only (flushing, urticaria)
• Grade II: Moderate multi-organ involvement (hypotension, tachycardia, bronchospasm)
• Grade III: Life-threatening hypotension or bronchospasm
• Grade IV: Cardiac or respiratory arrest

Immediate Management Algorithm

For Any Allergic Symptoms:

1. Stop the offending agent (IV antibiotic) immediately
2. Maintain airway and administer oxygen if needed
3. Position the patient appropriately (supine with legs elevated if hypotensive)

Medication Administration Based on Severity:

For Grade I (Mild) Reactions:

• Administer IM adrenaline 0.5 mg (0.5 mL of 1:1000 solution) in adults 1
• Monitor closely for progression to more severe symptoms

For Grade II (Moderate) Reactions:

• Administer IV adrenaline 20-50 μg (0.2-0.5 mL of 1:10,000 solution) 1
• Administer crystalloid 500 mL as rapid bolus 1
• Repeat adrenaline dose after 2 minutes if inadequate response

For Grade III (Severe) Reactions:

• Administer IV adrenaline 100-200 μg (1-2 mL of 1:10,000 solution) 1
• Administer crystalloid 1 L as rapid bolus and repeat if needed 1

For Grade IV (Cardiac/Respiratory Arrest):

• Follow advanced life support guidelines including IV adrenaline 1 mg 1
• Initiate cardiac compressions

Pediatric Dosing

• >12 years: 500 μg IM (0.5 mL of 1:1000 solution)
• 6-12 years: 300 μg IM (0.3 mL of 1:1000 solution)
• <6 years: 150 μg IM (0.15 mL of 1:1000 solution) 1

Secondary Management

After initial adrenaline and fluid resuscitation:

1. Administer chlorphenamine 10 mg IV (adult dose) 1
2. Administer hydrocortisone 200 mg IV (adult dose) 1
3. For persistent bronchospasm: Consider inhaled or IV bronchodilators 1
4. For persistent hypotension: Consider starting an adrenaline infusion (0.05-0.1 μg/kg/min) 1

Important Considerations

• Early intervention is critical: Allergic reactions to IV antibiotics can progress rapidly to life-threatening anaphylaxis within minutes 1
• Route of administration: IM is preferred in most settings, but IV is appropriate when IV access is already established and trained personnel are present 1
• Monitoring: All patients should be observed for at least 6 hours after treatment, as biphasic reactions can occur 1
• Laboratory testing: Obtain mast cell tryptase levels (ideally at 1-2 hours after reaction onset and again at 24 hours) 1

Common Pitfalls to Avoid

1. Delayed administration of adrenaline: This is the most common error in managing allergic reactions and can lead to increased morbidity and mortality 2
2. Incorrect dosing or route: Many healthcare providers are unfamiliar with correct adrenaline dosing 2
3. Overreliance on antihistamines and corticosteroids: These are second-line treatments and should never be used alone in place of adrenaline 1
4. Failure to remove the triggering agent: Continuing the IV antibiotic infusion can worsen the reaction 1
5. Inadequate fluid resuscitation: Sufficient fluid administration is essential to combat vasodilatation 1

Remember that allergic reactions to IV antibiotics can progress rapidly, and early administration of adrenaline is the cornerstone of effective management to prevent progression to life-threatening anaphylaxis.