Why adrenaline dosing in anaphylaxis must be routine
Anaphylaxis often progresses rapidly and is difficult to predict. Most errors arise not from a lack of knowledge but from the process itself: adrenaline is given too late, by the wrong route or at the wrong concentration. In addition, antihistamines and glucocorticoids are frequently given first.
The principle is simple: if anaphylaxis with airway or circulatory involvement is suspected, adrenaline is given intramuscularly immediately. Everything else follows.
Immediate measures at a glance
Initial management runs in parallel rather than sequentially:
- Stop the trigger, e.g. discontinue an infusion or drug administration
- Call for help
- Adrenaline i.m. into the lateral thigh
- Positioning according to the leading symptom
- Oxygen at high flow
- Fluids crystalloid
Severity grades and indication for adrenaline
Grading is based on organ involvement:
| Grade | Skin | Abdomen | Airway | Circulation |
|---|---|---|---|---|
| I | Pruritus, flushing, urticaria, angioedema | – | – | – |
| II | as I | Nausea, cramps, vomiting | Rhinorrhoea, hoarseness, dyspnoea | Tachycardia, drop in blood pressure, arrhythmia |
| III | as I | Vomiting, defecation | Laryngeal oedema, bronchospasm, cyanosis | Shock |
| IV | as I | as III | Respiratory arrest | Cardiac arrest |
Two points are decisive in practice:
- Skin symptoms may be absent. The absence of a rash does not exclude anaphylaxis.
- Adrenaline i.m. is indicated from grade II onwards, i.e. as soon as the airway or circulation is involved.
In cardiac arrest (grade IV), the resuscitation algorithm applies. In this setting, adrenaline is given i.v./i.o. according to the ERC Guidelines 2025:
- Adults: 1 mg every 3–5 min
- Children: 0.01 mg/kg, max. 1 mg, every 4 min
Adrenaline i.m. in anaphylaxis: dose and technique
Injection site and preparation
- Injection site: anterolateral thigh, middle third
- Concentration: undiluted, 1 mg/ml (1 ml = 1 mg)
- Timing: immediately on suspicion
There are no absolute contraindications to adrenaline in anaphylaxis. Intramuscular administration should therefore not be withheld in patients with pre-existing conditions.
Weight-based dose
According to the ERC Guidelines 2025 (Paediatric Life Support):
- 0.01 mg/kg (10 µg/kg) i.m.
- maximum 0.5 mg per single dose
- Repeat every 5 min as long as there is no improvement
At a concentration of 1 mg/ml, this gives:
| Body weight | Dose | Volume (1 mg/ml) |
|---|---|---|
| 3 kg | 0.03 mg | 0.03 ml |
| 5 kg | 0.05 mg | 0.05 ml |
| 10 kg | 0.1 mg | 0.1 ml |
| 15 kg | 0.15 mg | 0.15 ml |
| 20 kg | 0.2 mg | 0.2 ml |
| 25 kg | 0.25 mg | 0.25 ml |
| 30 kg | 0.3 mg | 0.3 ml |
| 40 kg | 0.4 mg | 0.4 ml |
Fixed age-based dose
If the weight is unknown or time is short, the ERC Guidelines 2025 provide fixed age-based doses:
| Age | Adrenaline i.m. |
|---|---|
| > 12 years and adults | 0.5 mg |
| 6–12 years | 0.3 mg |
| 1–5 years | 0.15 mg |
| < 1 year | 0.01 mg/kg |
The age-based dose simplifies management, particularly in prehospital paediatric emergencies. Small-volume syringes help to draw up the small volumes required for infants and young children accurately.
Repeat dosing
If symptoms do not improve, adrenaline i.m. is repeated after 5 min. Clinical criteria are:
- Airway symptoms
- Blood pressure
- Perfusion
- Level of consciousness
To adhere to the interval, the time of the first dose should be documented and communicated within the team.
When to give adrenaline intravenously?
Intravenous administration is intended for two situations:
- Refractory anaphylaxis: symptoms persist despite two i.m. doses.
- The patient is already monitored, e.g. in the resuscitation room, the operating theatre or the intensive care unit.
For infusion, the compendium describes the following approach:
- Start at 0.1 µg/kg/min, then titrate to effect
- Administration titrated and diluted, as a bolus or via syringe driver
- only by experienced clinicians under full monitoring
For dilution, in addition to the stock solution of 1 mg/ml, a 0.1 mg/ml preparation is available (1 mg made up to 10 ml with NaCl 0.9 %). Specific i.v. bolus doses as well as syringe driver dilutions and infusion rates should follow local protocols, the current guideline and the summary of product characteristics.
A typical risk of error is mix-up: undiluted adrenaline at the i.m. dose must not be given as an intravenous bolus. Label syringes clearly and state concentrations aloud within the team (closed-loop communication).
Adverse effects and practical notes
- Tachycardia, arrhythmias, hypertension and myocardial ischaemia may occur. This is a further reason to give i.v. adrenaline only under monitoring.
- Adrenaline is inactivated when mixed with alkaline solutions, e.g. sodium bicarbonate. Flush the line accordingly.
Anaphylactic shock: therapy beyond adrenaline
Positioning
- Haemodynamically unstable: supine, legs elevated
- Dyspnoea: sitting up
- Unconscious: recovery position
Oxygen and fluids
- Oxygen at high flow
- Crystalloid fluids: adults 500–1000 ml, children 20 ml/kg, repeat according to effect
In anaphylactic shock in particular, fluid therapy is a mainstay alongside adrenaline, because vasodilation and capillary leak lead to relative and absolute hypovolaemia.
Bronchospasm
In bronchospasm, an inhaled β₂-agonist is given additionally. It complements systemic adrenaline but does not replace it.
Patients on beta-blockers
Patients on beta-blocker therapy often respond poorly to adrenaline. In this case, glucagon should be considered. For dosing, refer to the current guideline or summary of product characteristics.
Antihistamines and glucocorticoids
Antihistamines and glucocorticoids are second-line and do not replace adrenaline. Their administration must not delay adrenaline. For dosing, refer to the S2k guideline on anaphylaxis and the respective summary of product characteristics.
Aftercare and handover
Management is not complete even after rapid improvement:
- Observation: a biphasic course is possible. Severe reactions require hospital admission.
- Serum tryptase should be taken to confirm the diagnosis.
- Prescribe an adrenaline auto-injector, draw up an emergency action plan and arrange an allergy work-up.
For handover, it is useful to document:
- suspected trigger
- time and number of adrenaline doses
- route of administration
- volume of fluids given
- course of the leading symptoms
Key points for the pocket
- Adrenaline i.m. from grade II onwards, i.e. with airway or circulatory involvement, immediately and undiluted into the anterolateral thigh.
- Dose 0.01 mg/kg, max. 0.5 mg. Alternatively by age: > 12 y/adults 0.5 mg, 6–12 y 0.3 mg, 1–5 y 0.15 mg, < 1 y 0.01 mg/kg.
- Repeat after 5 min if there is no improvement.
- After two unsuccessful i.m. doses or if the patient is already monitored: adrenaline i.v., diluted and titrated, as an infusion starting at 0.1 µg/kg/min. Only by experienced clinicians.
- Positioning according to the leading symptom, high-flow oxygen, crystalloid fluids.
- Antihistamines and glucocorticoids are second-line. Consider glucagon in patients on beta-blockers.
- Observe for a possible biphasic course, take tryptase, prescribe an auto-injector.
References
- Djakow J, Turner NM, Skellett S et al. European Resuscitation Council Guidelines 2025 Paediatric Life Support. Resuscitation 2025;215 Suppl 1:110767.
- Soar J, Böttiger BW et al. European Resuscitation Council Guidelines 2025 Adult Advanced Life Support. Resuscitation 2025;215 Suppl 1:110769 (Korrigendum 2026).
- Ring J et al. S2k-Leitlinie Akuttherapie und Management der Anaphylaxie (AWMF 061-025). Allergo J Int 2021;30:1–25.
- Lott C et al. European Resuscitation Council Guidelines 2021: Cardiac arrest in special circumstances (Anaphylaxie). Resuscitation 2021;161:152–219.
This article does not replace clinical judgement in the individual case or the current summary of product characteristics and guidelines.
