What is the proper administration of adrenaline (epinephrine) for anaphylaxis treatment?

Anaphylaxis Treatment: Adrenaline (Epinephrine) Administration

Administer epinephrine 0.3-0.5 mg intramuscularly into the anterolateral thigh immediately upon recognizing anaphylaxis—this is the only first-line treatment and delays in administration contribute to fatalities. 1, 2

Immediate Administration Protocol

Route and Site

• Intramuscular injection into the lateral thigh (vastus lateralis) is the mandatory route for first-aid and emergency treatment, producing peak plasma concentrations in 8 minutes compared to 34 minutes with subcutaneous injection 1, 3
• Never inject into buttocks, digits, hands, or feet due to risk of tissue necrosis 4
• The anterolateral thigh provides superior pharmacokinetics and is safer than intravenous administration in non-arrest situations 1, 2

Dosing

Adults and children ≥30 kg:

• 0.3-0.5 mg (0.3-0.5 mL of 1:1000 solution) intramuscularly 1, 4
• Autoinjectors deliver fixed 0.3 mg dose 1

Children <30 kg:

• 0.01 mg/kg (0.01 mL/kg of 1:1000 solution), maximum 0.3 mg 1, 2, 4
• Pediatric autoinjectors deliver 0.15 mg for children 10-25 kg 1

Repeat Dosing

• Repeat every 5-15 minutes as needed if symptoms persist or recur 1, 3
• Approximately 7-18% of patients require more than one dose 1
• If no response after 10 minutes and EMS arrival exceeds 5-10 minutes, repeat dose is indicated 1, 2

Intravenous Epinephrine (Advanced Settings Only)

Indications

• Reserved exclusively for cardiac arrest, profound hypotension unresponsive to multiple IM doses, or when IV access is already established 1, 2
• Requires continuous hemodynamic monitoring including ECG, blood pressure every minute, and heart rate 2, 3

IV Dosing

For severe hypotension (non-arrest):

• 0.05-0.1 mg (50-100 mcg) of 1:10,000 solution administered slowly 1, 3
• Pediatric dose: 0.01 mg/kg (maximum 0.3 mg) given slowly over several minutes 2

For cardiac arrest:

• 1 mg (1:10,000 solution) per standard ACLS protocol 1

For refractory cases:

• Continuous infusion at 5-15 mcg/min (adults) or 0.05-0.1 mcg/kg/min (children) 1, 2, 3
• Prepare by adding 1 mg epinephrine to 250 mL D5W for 4 mcg/mL concentration 2

Critical Supportive Measures

Immediate Actions

• Activate emergency response system immediately—approximately 500-1000 Americans die annually from anaphylaxis 1
• Position patient supine with legs elevated unless respiratory distress prevents this 3
• Administer 100% oxygen and monitor oxygen saturation continuously 1, 3
• Establish IV access and give crystalloid bolus: 500-1000 mL for adults, 20 mL/kg for children 2, 3

Airway Management

• Rapid advanced airway management is critical for obstructive airway edema—emergency cricothyroidotomy or tracheostomy may be required 1
• Immediate referral to provider with surgical airway expertise is mandatory 1

Second-Line Adjunctive Therapies (Never Replace Epinephrine)

Antihistamines

• H1 antihistamines (diphenhydramine 25-50 mg IV) address only cutaneous symptoms and have slow onset (≥1 hour)—never administer before or instead of epinephrine 1, 2, 3
• H2 antihistamines (ranitidine 50 mg IV or famotidine 20 mg IV) may provide additional benefit when combined with H1 antagonists 3

Bronchodilators

• Inhaled albuterol (2.5-5 mg nebulized) for persistent bronchospasm unresponsive to epinephrine, particularly in patients with preexisting asthma 1, 3
• Consider IV aminophylline or magnesium sulfate for refractory bronchospasm 1

Corticosteroids

• Methylprednisolone 1-2 mg/kg IV (typically 40 mg every 6 hours for adults) or hydrocortisone 100-200 mg IV 1, 2, 3
• Provide no acute benefit but may prevent biphasic reactions—consider especially for patients with asthma, severe/prolonged reactions, or history of idiopathic anaphylaxis 2, 3
• Recent evidence questions efficacy in preventing biphasic reactions 1

Management of Refractory Anaphylaxis

Escalation Protocol

• If inadequate response after 10 minutes, double the epinephrine bolus dose 2
• After three boluses, initiate epinephrine infusion 2
• For persistent hypotension despite epinephrine, add norepinephrine infusion (0.05-0.5 mcg/kg/min) 2
• Consider vasopressin 1-2 units bolus with or without infusion (2 units/hour) 2

Special Population: Beta-Blocker Patients

• Patients on beta-blockers may be unresponsive to epinephrine and require glucagon 1, 3
• Adult dose: 1-5 mg IV over 5 minutes, followed by infusion of 5-15 mcg/min 2, 3
• Pediatric dose: 20-30 mcg/kg (maximum 1 mg) over 5 minutes 2, 3

Post-Treatment Management

Observation Period

• Observe minimum 6 hours in monitored area or until stable and symptoms regressing 2, 3
• Biphasic anaphylaxis occurs in 10.3% of cases (mean 11 hours after initial reaction, up to 72 hours) 1
• Patients requiring multiple epinephrine doses are at higher risk for biphasic reactions 1

Diagnostic Testing

• Obtain mast cell tryptase samples: first at 1 hour after onset, second at 2-4 hours, baseline at ≥24 hours post-reaction 2
• Label samples with time and date 1

Discharge Requirements

• Prescribe two epinephrine autoinjectors before discharge 2, 5
• Provide written personalized anaphylaxis emergency action plan 2
• Train patient/family on autoinjector use and anaphylaxis recognition 2
• Arrange allergist referral for trigger identification and consideration of allergen immunotherapy 2

Critical Pitfalls to Avoid

• Delayed epinephrine administration is the primary factor contributing to anaphylaxis fatalities—administer immediately when suspected 1, 2, 6
• Never substitute antihistamines or corticosteroids for epinephrine as first-line treatment 1, 2
• Do not administer IV epinephrine without continuous hemodynamic monitoring outside cardiac arrest 2
• Avoid premature discharge without adequate observation for biphasic reactions 2
• Adolescents and patients with severe uncontrolled asthma have particularly high risk for fatal anaphylaxis 2
• Presence of sulfite preservative in epinephrine formulations should never deter use for anaphylaxis 4