Epinephrine Dosing in Anaphylactic Shock
For adults and children ≥30 kg, administer 0.3-0.5 mg of epinephrine (1:1000 concentration) intramuscularly into the anterolateral thigh; for children <30 kg, administer 0.01 mg/kg (maximum 0.3 mg) intramuscularly, repeated every 5-15 minutes as needed. 1, 2
Adult Dosing
The recommended intramuscular dose for adults is 0.2-0.5 mg of epinephrine 1:1000 (1 mg/mL), repeated every 5-15 minutes as necessary. 1 The FDA-approved dosing specifies 0.3-0.5 mg for patients weighing ≥30 kg (66 lbs), with a maximum of 0.5 mg per injection. 2
- Intramuscular injection into the anterolateral thigh (vastus lateralis) is the preferred route because it produces rapid peak plasma epinephrine concentrations and is the most effective, safe, and easy to administer. 1
- Standard epinephrine autoinjectors deliver 0.3 mg per dose for adults. 1
- When IV access is established, consider IV epinephrine at 0.05-0.1 mg (1:10,000 concentration) as a reasonable alternative in anaphylactic shock, though this carries higher risk and requires careful titration. 1
- For refractory shock, IV infusion at 5-15 μg/min is a reasonable alternative to boluses, allowing for careful titration and avoiding overdosing. 1
Pediatric Dosing
For children <30 kg, the recommended dose is 0.01 mg/kg of epinephrine 1:1000 intramuscularly, up to a maximum of 0.3 mg per injection, repeated every 5-10 minutes as needed. 3, 4, 2
- Pediatric autoinjectors deliver 0.15 mg for children weighing 15-30 kg. 1
- For infants weighing 7.5-15 kg, a 0.1 mg autoinjector formulation is now available, providing better dosing accuracy than the 0.15 mg device. 5, 6
- For infants <7.5 kg where optimal dosing devices are unavailable, the 0.15 mg autoinjector remains recommended despite exceeding the per-kilogram dose, as the consequences of not receiving epinephrine can be fatal. 7
- When restraining young children for injection, hold the leg firmly in place to minimize injection-related injury. 2
Critical Administration Details
Inject into the anterolateral aspect of the mid-thigh through clothing if necessary, using a needle at least 1/2 to 5/8 inch long to ensure intramuscular delivery. 2 This site is superior to the arm (deltoid) or subcutaneous routes. 1, 3
- Do not inject into buttocks, digits, hands, or feet due to risk of tissue necrosis from vasoconstriction. 2
- Do not administer repeated injections at the same site for the same reason. 2
- Many patients require additional doses, with symptom recurrence after 5-15 minutes commonly reported. 1
Common Pitfalls to Avoid
Delayed epinephrine administration is associated with fatal anaphylaxis. 1, 8, 9, 10 Epinephrine should be administered immediately upon recognition of anaphylaxis—it is most effective when given at symptom onset. 10
- There is no absolute contraindication to epinephrine in anaphylaxis, even in patients with cardiovascular disease, elderly patients, or pregnant women, though these populations require careful monitoring. 3, 5, 2
- Antihistamines, inhaled beta-agonists, and corticosteroids are second-line therapies only and have no proven benefit during anaphylaxis-induced cardiac arrest. 1
- Avoid intravenous epinephrine unless specifically trained, as several anaphylaxis fatalities have been attributed to injudicious IV use. 3
- The subcutaneous route has delayed onset compared to intramuscular and should be avoided when IM administration is feasible. 10
Cardiac Arrest from Anaphylaxis
In cardiac arrest secondary to anaphylaxis, standard resuscitative measures and immediate epinephrine administration should take priority. 1 Standard ACLS protocols apply, with epinephrine as the cornerstone of management. 1
Monitoring and Follow-up
Close hemodynamic monitoring is essential as cardiovascular and respiratory status can change rapidly in anaphylactic shock. 1 Patients should be transported to an emergency department, preferably by EMS, for continued monitoring and potential additional interventions including supplemental oxygen and IV fluids. 8