Adult Epinephrine Dosing for Allergic Reactions
For adults experiencing anaphylaxis, administer 0.3 to 0.5 mg of epinephrine (1:1000 concentration) intramuscularly into the anterolateral thigh, repeating every 5-10 minutes as needed for persistent or recurrent symptoms. 1
Standard Intramuscular Dosing
The FDA-approved dose for adults and children ≥30 kg (66 lbs) is 0.3 to 0.5 mg (0.3 to 0.5 mL of 1:1000 solution) administered intramuscularly into the anterolateral aspect of the thigh 1
The injection should be repeated every 5-10 minutes as necessary based on clinical response and severity of the reaction 1
Approximately 6-19% of patients require a second dose of epinephrine 2
Intramuscular injection into the vastus lateralis (lateral thigh) is the preferred route, producing more rapid peak plasma concentrations compared to subcutaneous administration or injection into the deltoid 3, 2
Critical Administration Details
Use a needle at least 1/2 to 5/8 inch long to ensure intramuscular delivery 1
The injection may be administered through clothing if necessary 1
Do not administer repeated injections at the same site, as vasoconstriction may cause tissue necrosis 1
There are no absolute contraindications to epinephrine use in anaphylaxis, even in elderly patients with cardiovascular disease—the benefits far outweigh the risks 2, 3
Intravenous Epinephrine (Reserved for Specific Circumstances)
IV epinephrine should only be used in specific situations: cardiac arrest, profound hypotension unresponsive to IM epinephrine and IV fluids, or failure to respond to several injected doses 4, 2
IV Bolus Dosing (Perioperative Setting)
For graded perioperative allergic reactions, the British Journal of Anaesthesia consensus recommends 3:
- Grade II (moderate hypotension/bronchospasm): 20 mcg IV bolus, escalate to 50 mcg at 2 minutes if inadequate response
- Grade III (life-threatening hypotension/bronchospasm): 50 mcg IV bolus (or 100 mcg if unresponsive to other vasopressors/bronchodilators), escalate to 200 mcg at 2 minutes if needed
- Grade IV (cardiac/respiratory arrest): 1 mg IV, repeat per advanced life support guidelines
IV Infusion Dosing
Starting dose: 1-4 mcg/min, titrated up to a maximum of 10 mcg/min based on clinical response and side effects 4, 3
Preparation method: Add 1 mg (1 mL) of 1:1000 epinephrine to 250 mL of D5W to yield 4.0 mcg/mL concentration, infuse at 15-60 drops/min with microdrop apparatus 4, 3
Alternative preparation: Add 1 mg (1 mL) of 1:1000 epinephrine to 100 mL of saline (1:100,000 solution), infuse at 30-100 mL/hr (5-15 mcg/min) 4, 3
Continuous hemodynamic monitoring is essential when administering IV epinephrine 4
Common Pitfalls to Avoid
Do not inject into buttocks, digits, hands, or feet due to risk of tissue necrosis from vasoconstriction 1
Do not delay epinephrine administration—delayed use is associated with more serious anaphylaxis and fatalities 3
Do not use subcutaneous injection as the primary route, as onset of action is delayed compared to intramuscular administration 5
Antihistamines and corticosteroids are not substitutes for epinephrine and should only be used as adjunctive therapy 3
Do not use the 1:1000 concentration intravenously—if IV administration is necessary, use 1:10,000 dilution (0.05-0.1 mg or 0.5-1 mL) 2
Monitoring and Follow-up
Monitor the patient clinically for severity of allergic reaction and potential cardiac effects, with repeat doses titrated to effect 1
Call emergency medical services (9-1-1) immediately when caring for a person with suspected anaphylaxis 3
Inspect epinephrine visually before administration—do not use if the solution is colored, cloudy, or contains particulate matter 1