What is the recommended dose of adrenaline (epinephrine) for a patient of any age experiencing an anaphylactic reaction?

Adrenaline Dosing for Anaphylactic Reactions

For adults and children ≥30 kg, administer 0.3-0.5 mg (0.3-0.5 mL of 1:1000 solution) intramuscularly into the anterolateral thigh, repeated every 5-10 minutes as needed; for children <30 kg, give 0.01 mg/kg (maximum 0.3 mg) intramuscularly into the anterolateral thigh, repeated every 5-10 minutes as needed. 1

Age-Based Intramuscular Dosing Algorithm

Pediatric Patients:

• >12 years: 500 mcg (0.5 mL of 1:1000 solution) IM; use 300 mcg (0.3 mL) if the child is small 2
• 6-12 years: 300 mcg (0.3 mL of 1:1000 solution) IM 2
• Up to 6 years: 150 mcg (0.15 mL of 1:1000 solution) IM 2

Weight-Based Alternative:

• ≥30 kg (66 lbs): 0.3-0.5 mg IM 1
• <30 kg (66 lbs): 0.01 mg/kg (maximum 0.3 mg) IM 1

Critical Administration Details

Route and Site:

• The intramuscular route into the anterolateral aspect of the mid-thigh is mandatory as it produces the most rapid peak plasma concentrations compared to subcutaneous or intravenous routes 3, 1, 4
• Never inject into buttocks, digits, hands, or feet due to risk of tissue necrosis and inadequate absorption 1

Repeat Dosing Strategy:

• Repeat the same dose every 5-10 minutes as needed until symptoms resolve 3, 1
• No maximum number of doses exists—multiple doses are frequently required in severe hypotension or bronchospasm 3
• Many patients require 2-3 doses, with symptom recurrence after 5-15 minutes being common 3

Intravenous Adrenaline (Specialist Settings Only)

Pediatric IV Dosing (Operating Theatres/ICU Only):

• Only use if IV access already exists and provider is experienced with IV adrenaline 2
• Prepare 1 mL of 1:10,000 adrenaline per 10 kg body weight (equals 10 mcg/kg) 2
• Start with one-tenth of the syringe contents (1 mcg/kg) and titrate to response 2
• Children often respond to as little as 1 mcg/kg 2
• Exercise extreme caution with dose preparation—decimal point errors can be fatal 2

Transition to IV Infusion:

• If several IM doses fail to produce adequate response, consider transitioning to continuous IV epinephrine infusion in a monitored setting 3

Common Pitfalls and Critical Warnings

Dosing Errors:

• The most dangerous error is confusing 1:1000 (IM) with 1:10,000 (IV) concentrations—always verify concentration before administration 2
• Decimal point errors during IV preparation are potentially fatal 2

Delayed Administration:

• Failure to inject epinephrine promptly is the leading contributor to anaphylaxis fatalities 4, 5
• Epinephrine is most effective when given immediately at symptom onset 4
• Never delay epinephrine to administer antihistamines or corticosteroids first—these are adjunctive therapies only 3

Route Selection:

• Subcutaneous administration has delayed onset and is inferior to IM 4
• IV administration outside specialist settings carries excessive risk of arrhythmias and hypertensive crisis 6

Adjunctive Medications (After Epinephrine)

Antihistamines (Second-Line):

• Chlorphenamine: 10 mg IV/IM for adults; 5 mg for ages 6-12 years; 2.5 mg for ages 6 months-6 years; 250 mcg/kg for <6 months 2

Corticosteroids (Second-Line):

• Hydrocortisone: 200 mg IV/IM for adults; 100 mg for ages 6-12 years; 50 mg for ages 6 months-6 years; 25 mg for <6 months 2

Special Populations

Patients on Beta-Blockers:

• May have refractory bronchospasm and hypotension despite epinephrine 1
• Consider higher or more frequent epinephrine doses 3
• May require glucagon as rescue therapy 6

Cardiovascular Disease:

• Epinephrine may aggravate angina or produce arrhythmias, but the risk of death from untreated anaphylaxis far exceeds these risks 1
• The presence of cardiac disease should never deter epinephrine use in true anaphylaxis 6

Pregnancy:

• Pregnant women may be at greater risk of adverse reactions, but epinephrine remains the first-line treatment 1

Post-Treatment Monitoring

• Transfer all patients to appropriate critical care area for observation 2
• Obtain mast cell tryptase levels: initial sample during resuscitation, second at 1-2 hours, third at 24 hours or in convalescence 2
• Observe for biphasic reactions (symptom recurrence 4-12 hours later) 6
• All patients should be referred to allergy specialist for identification of trigger and long-term management 2, 6