Intramuscular Adrenaline Dosing for Adult Anaphylactic Shock
You should draw 0.5 mL from the 1:1000 (1mg/1mL) adrenaline ampoule for intramuscular administration in an adult patient with anaphylactic shock. 1, 2, 3
Direct Answer to Your Question
The question asks how many mLs to draw for "0.5mls" - this appears to be asking for confirmation of the correct dose, which is indeed 0.5 mL of the 1:1000 solution (equivalent to 500 micrograms or 0.5 mg of adrenaline). 1, 2, 3
Dosing Algorithm for Adults
Standard adult dose: 0.5 mL of 1:1000 solution (500 micrograms) administered intramuscularly into the anterolateral aspect of the mid-thigh 1, 2, 3
Acceptable range: 0.3-0.5 mL for adults weighing ≥30 kg (66 lbs), with 0.5 mL being the maximum single injection 2, 3
Repeat dosing: Every 5-15 minutes as needed until symptoms resolve, with no maximum number of doses specified 2
Critical Administration Details
Route and site matter significantly for survival:
Intramuscular injection into the anterolateral thigh is the preferred route - this produces the most rapid peak plasma concentrations compared to subcutaneous or other routes 2, 4
Never inject into buttocks, digits, hands, or feet due to risk of tissue injury 3
Do not confuse concentrations: The 1:1000 solution (1 mg/mL) is for IM use; the 1:10,000 solution (0.1 mg/mL) is for IV use in cardiac arrest 1
When to Repeat or Escalate
Multiple doses are frequently required in severe hypotension or bronchospasm 1, 2
Repeat the same 0.5 mL IM dose every 5-15 minutes if inadequate response 2, 3
Consider IV epinephrine infusion if several IM doses fail to produce adequate response 1, 2
No upper limit exists on the number of IM doses that can be administered 2
Common Pitfalls to Avoid
Dosing errors are a major cause of preventable harm:
Confusion about concentration: Only 14-17% of junior doctors correctly identify the proper dose and route for anaphylaxis 5, 6
Wrong route selection: IV administration of undiluted 1:1000 solution can cause fatal arrhythmias and cerebral hemorrhage 3
Delayed administration: Failure to inject epinephrine promptly contributes to anaphylaxis fatalities - it is most effective when given immediately 4
Underdosing: Some clinicians incorrectly use 0.3 mL when 0.5 mL is appropriate for most adults 3
Practical Memory Aid
"A Thigh 500" - Adrenaline into the anterolateral thigh, 500 micrograms (0.5 mL of 1:1000) 6