Intramuscular Adrenaline Dosing for Anaphylactic Shock
Draw 0.5 mL from the 1:1000 adrenaline ampoule to deliver the 0.5 mg dose for an adult patient in anaphylactic shock. 1, 2
Dosing Calculation and Administration
For adults (>12 years or ≥30 kg): The standard IM dose is 500 mcg (0.5 mg), which equals 0.5 mL of the 1:1000 solution 1, 2
Inject into the anterolateral aspect of the thigh (vastus lateralis muscle), which can be administered through clothing if necessary 2
Use a needle at least 1/2 to 5/8 inch long to ensure intramuscular (not subcutaneous) delivery 2
The intramuscular route in the thigh produces the most rapid peak plasma concentrations compared to subcutaneous or other sites 1, 3
Repeat Dosing Strategy
Repeat the 0.5 mL dose every 5-10 minutes as necessary if symptoms persist or recur 2
Multiple doses are frequently required in severe hypotension or bronchospasm 1, 3
There is no maximum number of doses that can be administered 3
Do not inject repeatedly at the same site due to risk of tissue necrosis from vasoconstriction 2
Critical Considerations for Severe Cases
If several IM doses fail to produce adequate response, consider transitioning to an intravenous epinephrine infusion 1, 3
IV epinephrine should only be used in cardiac arrest or profound hypotension unresponsive to multiple IM doses and IV fluid resuscitation 1
For IV administration: Initial dose is 50 mcg (0.5 mL of 1:10,000 solution), NOT 1:1000 1
Common Pitfalls to Avoid
Never confuse 1:1000 with 1:10,000 concentrations - this is a 10-fold dosing error that can be fatal 1
Do not delay adrenaline administration - it should be given as early as possible, before adjunct medications like antihistamines or corticosteroids 1, 4, 5
Avoid injecting into buttocks, digits, hands, or feet due to risk of tissue necrosis 2
Do not use subcutaneous route - IM administration in the thigh is superior for achieving rapid therapeutic levels 1, 3