What is the recommended epinephrine (adrenaline) dose for anaphylaxis in adults and children, including weight‑based intramuscular dosing and repeat dosing recommendations?

Epinephrine Dosing for Anaphylaxis

Administer intramuscular epinephrine 0.01 mg/kg (1:1000 concentration) immediately into the anterolateral thigh: maximum 0.5 mg for adults and 0.3 mg for children, repeated every 5-15 minutes as needed. 1, 2, 3

Adult Dosing

• Standard dose: 0.3 to 0.5 mg of 1:1000 epinephrine (0.3-0.5 mL) intramuscularly into the anterolateral thigh 2, 3
• Repeat dosing: Every 5-15 minutes based on clinical response 1, 2, 3
• Approximately 6-19% of adults require a second dose 2
• Use a needle at least 1/2 to 5/8 inch long to ensure intramuscular delivery 3

Pediatric Dosing

Weight-Based Dosing

• Children <30 kg: 0.01 mg/kg (0.01 mL/kg of 1:1000 solution) up to maximum 0.3 mg per injection 1, 3
• Children ≥30 kg: 0.3 to 0.5 mg (same as adult dosing) 3
• Repeat every 5-10 minutes as clinically indicated 3

Autoinjector Dosing by Weight

• 7.5-15 kg: 0.1 mg autoinjector (newly available formulation) 1, 4
• 10-25 kg: 0.15 mg autoinjector 5
• ≥25 kg: 0.3 mg autoinjector 5
• For infants <7.5 kg, the 0.15 mg autoinjector is still preferable to ampule/syringe methods despite slight overdosing, as manual dosing carries 40-fold variation in accuracy and dangerous delays 6

Route and Site of Administration

The intramuscular route into the anterolateral thigh (vastus lateralis) is mandatory for first-line treatment. 2, 5

• IM injection in the lateral thigh achieves peak plasma concentration at 8±2 minutes versus 34±14 minutes with subcutaneous injection 5
• Inject at a 90-degree angle perpendicular to the skin to ensure muscle penetration 5
• Can be administered through clothing if necessary—do not delay 5
• Avoid the deltoid muscle, which provides inferior absorption compared to the thigh 5
• Do not inject repeatedly at the same site due to risk of tissue necrosis from vasoconstriction 3

Refractory Anaphylaxis: IV Epinephrine

Reserve intravenous epinephrine exclusively for cardiac arrest or profound hypotension unresponsive to multiple IM doses and aggressive fluid resuscitation. 2, 6

IV Bolus Dosing

• Adults: 0.1-0.5 mg (1-5 mL of 1:10,000 solution) given slowly over several minutes with continuous cardiac monitoring 2
• Children: 0.01 mg/kg (0.1 mL/kg of 1:10,000 solution; maximum 0.3 mg) given slowly over several minutes 6

IV Infusion Protocol

• Add 1 mg (1 mL of 1:1000) epinephrine to 1000 mL of 0.9% normal saline 1
• Start at 2 μg/min (2 mL/min or 120 mL/h) 1, 2
• Titrate up to maximum 10 μg/min (10 mL/min or 600 mL/h) based on blood pressure, heart rate, and oxygenation 1, 2
• Alternative concentration: 1 mg in 250 mL D5W (4 μg/mL) at 1-4 μg/min 6

Special Populations and Considerations

No Absolute Contraindications

• Epinephrine has no absolute contraindications in anaphylaxis, even in elderly patients with cardiac disease, hypertension, or other comorbidities 1, 2, 5
• The benefits of epinephrine far outweigh risks of adverse effects (transient pallor, tremor, anxiety, palpitations) 2

Patients on Beta-Blockers

• May be refractory to epinephrine 6
• Consider IV glucagon 1-2 mg (20-30 μg/kg in children, maximum 1 mg) over 5 minutes for refractory symptoms 6

Infants and Small Children

• For infants weighing >7.5 kg, the speed and precision of a 0.15 mg autoinjector outweighs theoretical overdosing concerns compared to error-prone manual dosing 1
• Hold the child's leg firmly and limit movement during injection to prevent needle injury 3

Critical Pitfalls to Avoid

• Never delay epinephrine while administering antihistamines or corticosteroids first—delay is associated with fatal outcomes 5, 6, 7
• Never use subcutaneous route instead of intramuscular, which delays absorption by 4-fold 5
• Never withhold epinephrine due to fear of adverse effects—mortality risk from untreated anaphylaxis far exceeds epinephrine risks 1, 2
• Never use ampule/syringe/needle for home use due to 40-fold dosing variation and dangerous delays 6
• Never administer IV epinephrine in non-arrest situations without continuous cardiac monitoring and appropriate expertise 6, 8
• Do not confuse concentrations: IM uses 1:1000 (1 mg/mL); IV uses 1:10,000 (0.1 mg/mL) 3
• Do not underdose by using pediatric autoinjectors in children ≥25 kg—switch to adult 0.3 mg dose at this threshold 5