What is the recommended dose of epinephrine (adrenaline) for anaphylaxis?

Epinephrine Dosing for Anaphylaxis

Administer epinephrine 0.01 mg/kg of 1:1000 solution (maximum 0.3 mg in children, 0.5 mg in adults) intramuscularly into the mid-anterolateral thigh immediately upon recognition of anaphylaxis, repeating every 5-15 minutes as needed for persistent or recurrent symptoms. 1, 2

Standard Dosing by Weight

Adults and Children ≥30 kg

• Dose: 0.3 to 0.5 mg (0.3 to 0.5 mL of 1:1000 solution) intramuscularly into the anterolateral thigh 2, 3
• Repeat every 5-10 minutes as necessary if symptoms persist 3
• Approximately 6-19% of patients require a second dose 2

Children <30 kg

• Dose: 0.01 mg/kg (0.01 mL/kg of 1:1000 solution), maximum 0.3 mg per injection 1, 3
• Repeat every 5-10 minutes as necessary 3

Autoinjector Dosing Guidelines

The FDA-approved autoinjectors come in fixed doses, creating practical dosing challenges across the pediatric weight spectrum 4:

Weight-Based Autoinjector Selection

• 7.5-25 kg: Use 0.15 mg autoinjector 2
• ≥25 kg: Use 0.3 mg autoinjector 4, 2
• ≥45 kg: Consider 0.5 mg autoinjector based on shared decision-making, as the 0.3 mg dose increasingly underdoses patients as weight increases above 30 kg 5

Critical Considerations for Infants <15 kg

For infants weighing less than 15 kg, pediatricians face a significant dilemma. The 0.15 mg autoinjector is still preferable to ampule/syringe/needle methods despite theoretical overdosing concerns 1. The ampule/syringe/needle technique carries a 40-fold variation in dosing accuracy, significant delays, and high error rates that outweigh theoretical overdosing risks 1. Many pediatricians (95% for infants 6-12 months) opt for the certainty of an autoinjector dose over the uncertainty of manual dosing 4.

Route of Administration: Critical Pharmacokinetic Differences

Intramuscular injection into the lateral thigh (vastus lateralis muscle) is the only acceptable first-line route 4, 1, 2. The pharmacokinetic superiority is dramatic:

• IM lateral thigh: Peak plasma concentration at 8 ± 2 minutes 4, 1
• Subcutaneous deltoid: Peak plasma concentration at 34 ± 14 minutes (range 5-120 minutes) 4

This difference is potentially life-saving, as achieving high plasma concentrations rapidly is critical for reversing hypotension in anaphylaxis 4.

Intravenous Epinephrine: Reserved for Refractory Cases Only

IV epinephrine should be reserved exclusively for cardiac arrest or profound hypotension unresponsive to multiple IM doses and aggressive fluid resuscitation 1, 3. The IV route carries significant risks of dilution errors, dosing errors, and serious adverse effects from inadvertent overdosing 4, 1.

IV Dosing When Indicated

• Cardiac arrest (Grade IV): 1 mg IV bolus 1
• Severe hypotension (Grade III): 50-100 μg IV bolus 1
• Moderate hypotension (Grade II): 20 μg IV bolus 1
• Continuous infusion: 0.05-0.1 μg/kg/min, starting after more than three boluses have been administered 1

IV Preparation

Add 1 mg (1 mL of 1:1000) epinephrine to 1000 mL of 0.9% normal saline, starting at 2 μg/min (120 mL/h) and titrating up to 10 μg/min (600 mL/h) based on blood pressure, heart rate, and oxygenation 2, 6. Continuous hemodynamic monitoring is mandatory 1.

Repeat Dosing Strategy

If inadequate response after 10 minutes, double the epinephrine bolus dose 1. The evidence suggests that repeat dosing every 5-15 minutes is safe and often necessary 1, 2. Transient adverse effects (pallor, tremor, anxiety, palpitations) are expected and do not contraindicate repeat dosing 4.

Management of Refractory Anaphylaxis

For patients not responding to standard IM epinephrine:

• After 3 boluses: Start epinephrine infusion (0.05-0.1 μg/kg/min) 1
• Persistent hypotension: Add norepinephrine infusion (0.05-0.5 μg/kg/min) 1
• Consider vasopressin 1-2 IU bolus for refractory hypotension 1
• Patients on beta-blockers: Administer IV glucagon 1-2 mg for refractory symptoms 1

Critical Pitfalls to Avoid

Delayed epinephrine administration is the single most important factor associated with anaphylaxis fatalities 1, 7. Common errors include:

• Never substitute antihistamines or corticosteroids for epinephrine as first-line treatment 1. H1 antihistamines have slow onset (≥1 hour) and do not relieve respiratory symptoms or shock 1.
• Do not withhold epinephrine due to fear of adverse effects in elderly patients or those with cardiovascular disease—there are no absolute contraindications to epinephrine in anaphylaxis 2, 6
• Avoid subcutaneous administration, which delays peak concentrations by 26 minutes compared to IM 4
• Do not inject into buttocks, digits, hands, or feet 3
• Observe patients for minimum 6 hours post-treatment to monitor for biphasic reactions 1

Special Populations

Patients on Beta-Blockers

These patients may be unresponsive to epinephrine and require glucagon 1-5 mg IV (20-30 μg/kg in children, maximum 1 mg) over 5 minutes 1.

High-Risk Patients

Adolescents and patients with severe uncontrolled asthma are at particularly high risk for fatal anaphylaxis and may warrant switching to the 0.3 mg autoinjector at lower weights 4, 1.