What is the recommended epinephrine treatment plan for an adult or child patient with no known medical history who has experienced anaphylaxis or cardiac arrest?

Epinephrine Treatment Plan for Anaphylaxis and Cardiac Arrest

Anaphylaxis Management

For anaphylaxis, immediately administer epinephrine 0.3-0.5 mg (1:1000 concentration) intramuscularly into the anterolateral thigh, repeating every 5-15 minutes as needed—this is the cornerstone of treatment and should never be delayed. 1, 2, 3

Initial Dosing and Route

• Adults and children ≥30 kg: Give 0.3-0.5 mg (0.3-0.5 mL of 1:1000) IM into the vastus lateralis (anterolateral thigh) 2, 3
• Children <30 kg: Give 0.01 mg/kg (0.01 mL/kg of 1:1000) IM, maximum 0.3 mg 2, 3
• The intramuscular route into the thigh produces the fastest peak plasma concentrations and avoids the severe hypertension and cardiac complications that can occur with IV overdose 1, 2
• Repeat doses every 5-15 minutes without limit—many patients require multiple doses due to symptom recurrence 1, 2

Critical Pitfall: Dosing Confusion

Never confuse anaphylaxis dosing (1:1000 IM) with cardiac arrest dosing (1:10,000 IV)—this error has caused fatal cardiac complications including severe systolic dysfunction and ventricular arrhythmias. 4 Stock prefilled, clearly labeled IM epinephrine syringes in crash carts to prevent this potentially lethal mistake 4.

Escalation for Refractory Anaphylaxis

If the patient develops profound hypotension or shock despite multiple IM doses and IV volume replacement, escalate to IV epinephrine:

• IV bolus: 0.05-0.1 mg (50-100 mcg) using 1:10,000 concentration 2
• IV infusion: 5-15 mcg/min (0.05-0.1 mcg/kg/min), titrated to response 5, 2
• Alternative preparation: Add 1 mg (1 mL of 1:1000) to 250 mL D5W for 4 mcg/mL concentration, infuse at 1-4 mcg/min initially, maximum 10 mcg/min 5
• Mandatory: Continuous hemodynamic monitoring with every-minute blood pressure, pulse, and ECG when using IV epinephrine 5

Adjunctive Therapies (Second-Line Only)

• H1 antihistamine: Diphenhydramine 25-50 mg IV/IM (1-2 mg/kg in children)—never use alone, only after epinephrine 5
• H2 antihistamine: Ranitidine 50 mg IV in adults, 1 mg/kg (12.5-50 mg) in children over 5 minutes—combination with H1 is superior to H1 alone but still second-line 5
• Bronchospasm resistant to epinephrine: Nebulized albuterol 2.5-5 mg in 3 mL saline, repeat as needed 5, 2
• Refractory hypotension: Dopamine infusion 2-20 mcg/kg/min titrated to maintain systolic BP >90 mmHg 5
• Beta-blocker complication: Glucagon 1-5 mg IV over 5 minutes, then 5-15 mcg/min infusion (20-30 mcg/kg in children, max 1 mg) 5, 2
• Corticosteroids: Consider methylprednisolone equivalent 1-2 mg/kg/day IV q6h for patients with asthma history or severe/prolonged anaphylaxis—not helpful acutely but may prevent biphasic reactions 5

Airway Management

• Perform immediate advanced airway management (intubation) when anaphylaxis produces obstructive airway edema 1
• Emergency cricothyroidotomy or tracheostomy may be required for severe laryngeal edema 1

Special Considerations

• Patients on beta-blockers may have refractory hypotension despite epinephrine and require glucagon as described above 2
• Cardiotoxicity occurs in approximately 5% of patients receiving IM epinephrine, more commonly in older patients with comorbidities or those requiring multiple doses—this includes ischemic ECG changes (2.4%), elevated troponin (1.8%), and arrhythmias (1.8%) 6
• Despite this risk, the presence of sulfites in epinephrine formulations should never deter use for anaphylaxis 3
• Refractory anaphylaxis can progress to cardiac arrest within minutes despite prompt management—if potentially fatal symptoms develop, use IV epinephrine infusion aggressively 7

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Cardiac Arrest Management

For cardiac arrest, administer epinephrine 1 mg IV/IO (1:10,000 concentration) every 3-5 minutes during ongoing resuscitation—early administration within 1-3 minutes improves return of spontaneous circulation and survival, particularly for non-shockable rhythms. 2, 8

Standard Dosing Protocol

• Adults: 1 mg IV/IO (1:10,000 concentration) every 3-5 minutes throughout resuscitation 2
• Children: 0.01 mg/kg (0.1 mL/kg of 1:10,000) IV/IO every 3-5 minutes, maximum 1 mg per dose 2
• Early administration (within 1-3 minutes) is associated with improved return of spontaneous circulation, survival to discharge, and neurologically intact survival for asystole/PEA 2
• High-dose epinephrine (0.1-0.2 mg/kg) does not improve survival or neurological outcomes and may worsen post-arrest outcomes—do not use 2

Anaphylaxis-Induced Cardiac Arrest

For cardiac arrest specifically caused by anaphylaxis, use high-dose IV epinephrine with rapid escalation:

• Initial: 1-3 mg (1:10,000) IV slowly over 3 minutes 5
• Second dose: 3-5 mg IV over 3 minutes 5
• Then: 4-10 mg/min infusion 5
• Children: 0.01 mg/kg (0.1 mL/kg of 1:10,000) up to 10 mg/min infusion rate 5
• Continue full cardiopulmonary resuscitation and advanced cardiac life support measures 5
• Note: Antihistamines, beta-agonists, and corticosteroids have no proven benefit during anaphylaxis-induced cardiac arrest 9

Route Considerations

• IV/IO is the preferred route for cardiac arrest 2, 8
• Intramuscular administration may have emerging benefits but requires further research 8
• Monitor for extravasation with IV use—tissue necrosis can occur, requiring phentolamine as antidote 2

Evidence Limitations

While epinephrine improves return of spontaneous circulation and survival to hospital discharge, it may not provide meaningful neurological recovery in many survivors 8. The β2-adrenergic receptor activation unique to epinephrine (compared to other vasopressors like norepinephrine) enhances pacemaker function and restores contractile function in ischemic cardiomyocytes, making it particularly useful when simple blood pressure elevation is insufficient 10.