What is the recommended adrenaline dose and administration route for anaphylaxis in adults and children?

Adrenaline Dosing in Anaphylaxis

Immediate First-Line Treatment

Administer intramuscular epinephrine immediately at 0.01 mg/kg of 1:1000 concentration (1 mg/mL) into the anterolateral thigh, with maximum doses of 0.5 mg in adults and 0.3 mg in children, and repeat every 5-15 minutes if symptoms persist. 1, 2

Specific Dosing by Weight

Adults and Adolescents

• Adults >50 kg: 0.3-0.5 mg (maximum 0.5 mg) of 1:1000 solution intramuscularly 1, 2
• The FDA-approved dose is 0.3-0.5 mL of undiluted Adrenalin® (1:1000) for patients ≥30 kg 2

Children

• Children <30 kg: 0.01 mg/kg (maximum 0.3 mg) of 1:1000 solution intramuscularly 1, 2
• Children and teenagers: Maximum single dose of 0.3 mg 1
• Infants 7.5-15 kg: 0.15 mg (or 0.1 mg with newer formulations where available) 1

Autoinjector Dosing

• 0.1 mg: For infants where available 1
• 0.15 mg: For children weighing 10-25 kg 3
• 0.30 mg: For individuals weighing ≥25 kg 3
• In settings without 0.1 mg autoinjectors, use 0.15 mg for infants >7.5 kg 3

Administration Route and Technique

Intramuscular (Preferred Route)

• Inject into the anterolateral thigh (vastus lateralis muscle) - this is vastly superior to all other routes 1, 3, 2
• The intramuscular route achieves peak plasma concentrations in 8±2 minutes, compared to 34±14 minutes with subcutaneous injection 1, 4
• Use a needle at least 1/2 to 5/8 inch long to ensure intramuscular delivery 2
• When administering to children, hold the leg firmly to minimize injection-related injury 2
• Can inject through clothing if necessary 2

Critical Route Comparison

• Never use subcutaneous epinephrine - the delayed absorption (34±14 minutes to peak) significantly compromises therapeutic efficacy and is associated with treatment failure 1, 4
• Avoid deltoid injection - the anterolateral thigh provides faster and higher plasma levels 3

Repeat Dosing Protocol

• Repeat every 5-15 minutes as needed if symptoms persist or worsen 1, 3, 2
• Approximately 7-18% of patients require more than one dose 1
• Do not inject repeatedly at the same site due to risk of tissue necrosis from vasoconstriction 2
• Monitor clinically for reaction severity and cardiac effects between doses 2

Intravenous Administration (Hospital Settings Only)

When to Consider IV Route

• Reserved exclusively for severe anaphylaxis unresponsive to intramuscular epinephrine in monitored hospital settings 1
• Only when IV access is already established and patient has anaphylactic shock unresponsive to multiple IM doses 3
• After failure of multiple IM injections or in cardiac arrest 3

IV Dosing Protocol

• Grade II reactions: 20 μg IV bolus 3
• Grade III reactions: 50-100 μg IV bolus 3
• Grade IV reactions (cardiac arrest): 1 mg IV following advanced life support guidelines 3
• Use 1:10,000 concentration (0.1 mg/mL) for IV bolus to avoid overdose 3
• Titrate slowly to response rather than rapid bolus 3

IV Infusion for Refractory Cases

• Consider when more than 3 IM boluses have been administered 3
• Dose: 0.05-0.1 μg/kg/min (or 1-4 μg/min in adults, titrated to maximum 10 μg/min) 1, 3
• Preparation: Add 1 mg (1 mL) of 1:1000 epinephrine to 250 mL D5W (concentration 4.0 μg/mL) 3
• Requires continuous cardiac monitoring for arrhythmias and hypertension 3

Critical Safety Considerations

Absolute Priorities

• Never delay epinephrine while administering antihistamines first - this is directly associated with increased mortality 1, 4
• There are no absolute contraindications to epinephrine use in anaphylaxis, even in elderly patients with cardiac disease 3, 4
• Delayed epinephrine administration is the primary factor in anaphylaxis fatalities 4, 5, 6

Common Pitfalls to Avoid

• Do not substitute antihistamines for epinephrine - antihistamines are solely second-line adjunctive therapy 1
• Do not delay IM injection while establishing IV access 3
• Do not use subcutaneous route due to significantly delayed absorption 1, 4
• Inspect solution before use - do not administer if colored, cloudy, or contains particulate matter 2

Adjunctive Therapies (After Epinephrine)

Fluid Resuscitation

• Grade II reactions: 0.5 L crystalloid bolus initially 3
• Grade III reactions: 1 L crystalloid bolus initially 3
• Repeat boluses up to 20-30 mL/kg based on clinical response 3

Antihistamines (Adjunctive Only)

• May be used only after epinephrine administration for cutaneous symptoms (urticaria, angioedema, pruritus) 1, 3
• H1 antihistamines: Diphenhydramine 25-50 mg IV or chlorphenamine 10 mg IV in adults 3
• These address only non-life-threatening symptoms and do not prevent cardiovascular collapse or airway obstruction 3, 4

Special Populations

• Patients on beta-blockers: May require glucagon 1-2 mg IV for refractory hypotension 3
• Pregnant women: Perform left uterine displacement to avoid aortocaval compression 3

Post-Treatment Management

Observation Period

• Minimum 6 hours in monitored area or until stable and symptoms resolved 1, 3
• Patients requiring >1 dose of epinephrine need extended observation due to higher risk of biphasic reactions 1
• Grade III-IV reactions typically require ICU admission 3

Discharge Requirements

• All patients must receive two epinephrine autoinjectors before discharge 3, 4
• Provide written, personalized anaphylaxis emergency action plan 3
• Refer to allergist for trigger identification and ongoing risk assessment 3
• Educate on monitoring autoinjector expiration dates 3

Tryptase Sampling

• First sample: 1 hour after reaction onset 3
• Second sample: 2-4 hours after onset 3
• Baseline sample: At least 24 hours post-reaction 3

Evidence Quality Note

The mortality from anaphylaxis is remarkably low at <0.5% per episode when treated appropriately with immediate epinephrine 1. These recommendations are based on consistent expert consensus from the American Academy of Allergy, Asthma, and Immunology, American College of Allergy, Asthma, and Immunology, American Academy of Pediatrics, and American Heart Association, though randomized controlled trials are lacking for ethical reasons 5, 7.