How the dose is calculated
Adrenaline is dosed as a single mg/kg amount per administration, capped at a maximum. Anaphylaxis uses the 1:1000 (1 mg/mL) concentration IM; cardiac arrest uses the more dilute 1:10,000 (0.1 mg/mL) concentration IV/IO — select the correct indication and concentration together.
Typical dosing by indication
| Indication | Dose | Frequency | Max |
|---|---|---|---|
| Anaphylaxis (IM) | 0.01 mg/kg | repeat every 5–15 min if needed | 0.5 mg per dose |
| Cardiac arrest (IV/IO) | 0.01 mg/kg | repeat every 3–5 min | 1 mg per dose |
Never confuse the two concentrations — 1:1000 (1 mg/mL) is for IM use in anaphylaxis; 1:10,000 (0.1 mg/mL) is the dilute IV/IO concentration used in cardiac arrest. Giving the undiluted 1:1000 strength intravenously is a serious, well-recognised medication error. Fixed-dose auto-injectors (e.g. 0.15 mg for roughly 7.5–25 kg, 0.3 mg above that) are commonly used in the community instead of a precisely calculated dose.
Clinical use
- IM adrenaline into the anterolateral thigh is the first-line treatment for anaphylaxis — give without delay at the first sign of a systemic allergic reaction; delay is associated with worse outcomes.
- Community and school settings typically use fixed-dose auto-injectors rather than a precisely calculated dose — the calculated value here helps decide which auto-injector strength is closest, not to draw up an exact syringe dose in that setting.
- IV/IO adrenaline for cardiac arrest is dosed and timed per current resuscitation council algorithms (e.g. every 3–5 minutes, alternating with rhythm checks) as part of the full ALS/PALS sequence, not as a standalone action.
- Repeat IM doses for anaphylaxis that isn't responding should prompt escalation of care (IV access, senior help, ICU/HDU) rather than repeated dosing alone.
Frequently asked questions
What is the difference between the two adrenaline concentrations?
1:1000 (1 mg/mL) is used undiluted for IM injection in anaphylaxis. 1:10,000 (0.1 mg/mL) is a ten-fold more dilute solution used for IV/IO administration in cardiac arrest — mixing these up is a serious and well-documented medication error.
Why is adrenaline given into the thigh for anaphylaxis?
The anterolateral thigh (vastus lateralis muscle) provides reliable, fast absorption of IM adrenaline, which is why it's the preferred site over the arm or buttock for anaphylaxis treatment.
How is an adrenaline auto-injector dose chosen for a child?
Auto-injectors come in fixed strengths (commonly 0.15 mg for smaller children and 0.3 mg for larger children/adults) rather than a precisely calculated dose — the weight-based calculation helps identify which fixed strength is the closest match, per the specific product's weight bands.
Can adrenaline doses for anaphylaxis be repeated?
Yes — if there's no improvement, a repeat IM dose can be given every 5–15 minutes while arranging further emergency care; anaphylaxis not responding to a couple of doses needs urgent escalation, not just further repeated dosing.
References
- Resuscitation Council UK. Emergency Treatment of Anaphylactic Reactions.
- American Heart Association. Pediatric Advanced Life Support (PALS) Guidelines.
- World Allergy Organization. Anaphylaxis Guidance.